OUTLINE

Epidemiology
Disease Associations
Pathogenesis
Laboratory/Radiologic/Other Diagnostic Testing
Gross Appearance and Clinical Variants
Histopathological Features and Variants
Special Stains/Immunohistochemistry/Electron Microscopy
Differential Diagnosis
Prognosis
Treatment
Commonly Used Terms
Internet Links

EPIDEMIOLOGY	CHARACTERIZATION
INCIDENCE	Most common benign soft tissue tumor in adults 1/1000 of general population
AGE RANGE-MEDIAN	40-60 years
SEX (M:F)	Slightly greater in M

 

DISEASE ASSOCIATIONS	CHARACTERIZATION
DFSP
Multiple spindle cell lipomas and dermatofibrosarcoma protuberans within a single patient: Evidence for a common neoplastic process of interstitial dendritic cells? Harvell JD. Department of Pathology, Stanford University Medical Center.	J Am Acad Dermatol 2003 Jan;48(1):82-5 Abstract quote This case report describes a 48-year-old man with multiple spindle cell lipomas of the neck and a dermatofibrosarcoma protuberans (DFSP) with fibrosarcomatous transformation of the chest. The presence of familial and nonfamilial multiple spindle cell lipomas within a single patient is a rare event, with only two reports in the current literature. This case represents the first report of multiple spindle cell lipomas occurring in association with a DFSP. It is of particular interest in that both spindle cell lipoma and DFSP represent, at least in part, neoplastic proliferations of CD34(+) spindled cells. The exact nature and differentiation of these spindled cells remains controversial, but prior studies have suggested that they could represent neoplastic interstitial dendritic cells. The association of DFSP and spindle cell lipoma within this single patient suggests that these two tumors (and their histologic variants) may well be linked, conceptually, as neoplastic proliferations of CD34(+) interstitial dendritic cells.

 

PATHOGENESIS	CHARACTERIZATION
Characteristic chromosomal abnormalities for lipoma	Translocations involving 12q13-15 Interstitial deletions of 13q Rearrangements involving 6p21-23

 

GROSS APPEARANCE/CLINICAL VARIANTS	CHARACTERIZATION
General
VARIANTS
BONE
Intracortical lipoma of the femur. Yamamoto T, Marui T, Akisue T, Hitora T, Nagira K, Ohta R, Yoshiya S, Kurosaka M. Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, Chuo-ku, Japan.	Am J Surg Pathol 2002 Jun;26(6):804-8 Abstract quote The authors report on a rare case of intracortical lipoma of the right femur in a 74-year-old woman. Magnetic resonance imaging and computed tomography of the femur demonstrated an intracortical lesion in the lateral diaphysis. No medullary involvement by the lesion was noted. Both imaging methods revealed the presence of fat in the lesion. Histologically, the tumor consisted of a large area of mature adipose tissues, admixed with foci of fat necrosis, calcification, and myxoid degeneration. Total excision of the tumor was curative. This is the second reported case of intracortical lipoma.
DERCUM'S DISEASE (ADIPOSA DOLOROSA)	Multiple painful lipomas or lipomatosis which arise in adult Usually occurs in middle aged women Usually obese Rare familial occurrence
Long-standing pain relief of adiposis dolorosa (Dercum's disease) after intravenous infusion of lidocaine. Juhlin L	J Am Acad Dermatol 1986 Aug;15(2 Pt 2):383-5 Abstract quote A 60-year-old woman with adiposis dolorosa for 20 years was treated with repeated intravenous infusions of lidocaine. Partial relief of pain in the legs was obtained after 1.3 gm. A dose of 5.2 gm lidocaine given for 4 days was needed for complete pain relief. The effect lasted for 3 weeks, and then the pain gradually returned. The patient has now been given two additional treatments with complete pain relief for 2 months. The mechanism of the effect remains unknown.
Adiposis dolorosa (Dercum's disease): liposuction as an effective form of treatment. DeFranzo AJ, Hall JH Jr, Herring SM. Department of Surgery, Bowman Gray School of Medicine.	Plast Reconstr Surg 1990 Feb;85(2):289-92 Abstract quote The clinical picture of adiposis dolorosa makes a lasting impression on the examining physician. The patient is typically an obese, asthenic woman who appears to have a low pain threshold. She has an unusual distribution of fatty tumors, and her complaint of pain in these tumors seems out of proportion to the physical findings. Alcoholism, emotional instability, and depression are common, and narcotic pain medicine is frequently requested. The patient is easily dismissed as a malingerer after a brief examination. However, liposuctioning of the painful fatty tumors appears to be both practical and effective. While adiposis dolorosa is an unusual disease, it is one that plastic surgeons can recognize and treat.
Fat-cell heat production, adipose tissue fatty acids, lipoprotein lipase activity and plasma lipoproteins in adiposis dolorosa. Fagher B, Monti M, Nilsson-Ehle P, Akesson B. Department of Internal Medicine, University Hospital of Lund, Sweden.	Clin Sci (Lond) 1991 Dec;81(6):793-8 Abstract quote 1. Gluteal adipose tissue was examined in 13 patients with generalized adiposis dolorosa, a clinical condition characterized by painful adiposity with a chronic intractable course. The total metabolic activity of fat cells, isolated by collagenase and suspended in Krebs-Ringer bicarbonate buffer with glucose and insulin, was assessed by the measurement of heat production at 37 degrees C using microcalorimetry. 2. Fat cells were markedly enlarged; their metabolic activity expressed in terms of microW/g, but not in pW/cell, was significantly decreased when compared with both lean and weight-matched non-painful subjects. Both mean values were, however, significantly higher than in grossly obese subjects with similar mean cell size. Heat production as expressed per g of tissue, but not per cell, was inversely correlated with body mass index. One additional patient had unilateral disease, and fat cells from the painful side had a lower heat production than cells from the unaffected side. 3. The fatty acid composition of adipose tissue, as determined by g.c., revealed a significantly increased proportion of monounsaturated (18:1 and 16:1) at the expense of saturated (14:0 and 18:0) fatty acids compared with healthy control subjects. The activity of adipose tissue lipoprotein lipase was slightly, but not significantly, decreased. 4. It is concluded that a metabolic pathogenetic factor cannot be ruled out in adiposis dolorosa. As the results do not explain the nature of the diffuse pain, further studies need to be performed.
Hormonal and metabolic study of a case of adiposis dolorosa (Dercum's disease). Pimenta WP, Paula FJ, Dick-de-Paula I, Piccinato CE, Monteiro CM, Brandao-Neto J, Kettelhut IC, Foss MC. Departamento de Clinica Medica, Faculdade de Medicina de Botucatu, Universidade Estadual Paulista, Botucatu, SP, Brasil.	Braz J Med Biol Res 1992;25(9):889-93 Abstract quote A case of a 43-year-old nonobese woman with adiposis dolorosa (Dercum's disease) is reported. Muscle glucose uptake and oxidation before and after ingestion of 75 g of glucose were similar to control group values, although a greater insulin release (16,578 vs 6,242 +/- 1,136 microU/3 h) occurred simultaneously. In vitro studies of abdominal normal and painful subcutaneous adipose tissue of the patient revealed lower responsiveness to norepinephrine and lack of response to the antilipolytic effect of insulin in the painful adipose tissue (0.98 vs 1.43 microM FFA/10(6) cells at 5.0 microM of norepinephrine). The disease was not correlated with the HLA system and there were no alterations in hormonal secretion at the pituitary, adrenal, gonadal, and thyroid levels. These findings indicate the presence of peripheral insulin resistance in this patient with adiposis dolorosa.
Adiposis dolorosa (Dercum's disease): 10-year follow-up. Brodovsky S, Westreich M, Leibowitz A, Schwartz Y. Department of Plastic Surgery, Assaf HaRofeh Medical Center, Tzrifin, Israel.	Ann Plast Surg 1994 Dec;33(6):664-8 Abstract quote Adiposis dolorosa is a disease characterized by painful, subcutaneous fatty tumors. This disorder usually occurs in obese, postmenopausal women and is associated with weakness and mental disturbances such as depression, confusion, lethargy, and dementia. The cause is unknown, and there is no specific treatment. Pain may be relieved by steroids, intravenous lidocaine, or analgesics. Surgical treatment consists of excision or liposuction of the painful masses. We present two cases of adiposis dolorosa in men, with a follow-up of more than 10 years.
Liposuction in Dercum's disease: impact on haemostatic factors associated with cardiovascular disease and insulin sensitivity. Berntorp E, Berntorp K, Brorson H, Frick K. Department of Coagulation Disorders, University of Lund, Malmo University Hospital, Sweden.	J Intern Med 1998 Mar;243(3):197-201 Abstract quote OBJECTIVE: To study the impact of adipose tissue removal by liposuction on factors associated with increased risk of cardiovascular atherosclerotic disease within the coagulation and fibrinolytic system and glucose metabolism. DESIGN, SETTING AND SUBJECTS: Liposuction was performed in 53 patients with Dercum's disease. The levels of fibrinogen, von Willebrand factor antigen (VWF:Ag) and plasminogen activator inhibitor type 1 activity (PAI-1) were measured preoperatively, and 2 weeks, 4 weeks and 3 months postoperatively. In a subsample of 10 patients, insulin sensitivity was determined before and 2-4 weeks after surgery using the 2-h euglycaemic hyperinsulinaemic clamp technique. The study was performed as a single-centre study. MAIN OUTCOME MEASURE: Fibrinogen, PAI-1 and VWF:Ag levels, and glucose uptake before and after removal of adipose tissue. RESULTS: Weight reduction was sustained throughout the follow-up period with a mean decrease from 90.7 to 86.6 kg (P < 0.0001). There was a slight increase in levels of coagulation factors 2 and 4 weeks postoperatively, probably in reaction to the surgical trauma. After 3 months the values had returned to preoperative levels except for PAI-1, which still showed a slight increase (P < 0.05). In the subsample of 10 patients, glucose uptake was improved (P < 0.05) from a short-term perspective after surgery. CONCLUSION: Surgical removal of adipose tissue, without change in lifestyle, does not seem to improve the levels of coagulation and fibrinolytic factors associated with cardiovascular atherosclerotic disease, whereas glucose takeup may be facilitated and insulin sensitivity increases from a short-term perspective.
Treatment of pain in adiposis dolorosa (Dercum's disease) with intravenous lidocaine: a case report with a 10-year follow-up. Devillers AC, Oranje AP.	Clin Exp Dermatol 1999 May;24(3):240-1
Familial occurrence of adiposis dolorosa. Campen R, Mankin H, Louis DN, Hirano M, Maccollin M. Department of Dermatology, Massachusetts General Hospital, Boston, MA, USA	J Am Acad Dermatol 2001 Jan;44(1):132-6 Abstract quote Adiposis dolorosa is a rare condition characterized by multiple painful lipomas. We describe two typically affected siblings who were found to have at least 5 affected first-degree relatives in two generations. Manifestations were remarkably variable, ranging from complete disability to solitary asymptomatic tumors. Review of histopathologic findings did not reveal any features that might distinguish the tumors from common sporadic lipomas. Mutational analysis excluded the 8344 A to G mitochondrial mutation seen in other patients with multiple lipomas. Adiposis dolorosa may be an extreme manifestation of the more common condition of familial multiple lipomas. Further work is needed to define the genetic basis of these conditions.
ORAL
Oral spindle cell lipoma Nasser Said-Al-Naief, DDS, MS Fazlur R. Zahurullah, MD James J. Sciubba, DMD, PhD From the Department of Pathology, the University of Alabama at Birmingham; the Department of Otolaryngology, Rockford Health System, Rockford, IL; and the Department of Otolaryngology Head and Neck Surgery, Division of Dental & Oral Medicine, Johns Hopkins University, Baltimore, MD.	Ann Diagn Pathol 5: 207-215, 2001. Abstract quote Lipoma is an uncommon benign, oral, soft-tissue neoplasm commonly found on the buccal mucosa. It is predominantly composed of mature fat with or without other mesenchymal tissue elements, showing a variety of histologic subtypes, one of which is the rare “spindle cell variant” with only nine previously reported cases in the English literature. In this report, we review clinical and histomorphologic data of 164 cases of oral lipomas retrieved from the files of Long Island Jewish Medical Center, Department of Dental Medicine (New Hyde Park, NY). Of these, only two cases were diagnosed as the spindle cell variant, further confirming the rarity of this histologic subtype. A review of oral lipoma with particular reference to the spindle cell variant is also presented.
VULVA
Intradermal spindle cell/pleomorphic lipoma of the vulva: case report and review of the literature Jorge S. Reis-Filho Fernanda Milanezi Maria F. Soares José Fillus-Neto Fernando C. Schmitt	J Cutan Pathol 2002;29:59 Abstract quote Background: Spindle cell/pleomorphic lipoma (SC/PL) is a benign adipose tissue tumor that usually affects the subcutaneous tissues of shoulders, backs, and neck region of middle-aged male patients. Histologically, it is characterized by the presence of primitive CD34-positive spindle cells arranged in short fascicles, bizarre floret-like multinucleated giant cells, mature adipocytes, and a small number of lipoblasts. Recently, an intradermal subset has been described, which mainly affects female patients and presents a wider antomical distribution when compared to the classical variant of SC/PL. Methods: We report a case of intradermal SC/PL affecting the labium majus of a 56-year-old female patient. Results: The histological examination disclosed the typical histological features, however the lesion showed poorly demarcated and infiltrative borders, as well as involvement of dermal nerves. The immunohistochemical analysis according to streptovidin-biotin-peroxidase technique showed immunoreactivity for CD34 and vimentin in the spindle cells, as well as S100 protein and vimentin in the adipocytic cells. Conclusions: To the best of our knowledge, this is the first case of intradermal SC/PL affecting the vulvar region. Care must be taken not to misdiagnosis this rare tumor as well-differentiated liposarcoma, cellular angiofibroma, solitary fibrous tumor, and cutaneous neurofibroma.

 

HISTOLOGICAL TYPES	CHARACTERIZATION
General	Circumscribed collection of mature adipose tissue
VARIANTS
Angiolipoma
Cellular angiolipoma. Hunt SJ, Santa Cruz DJ, Barr RJ. Department of Pathology, St. John's Mercy Medical Center, St. Louis, MO 63141-8221.	Am J Surg Pathol 1990 Jan;14(1):75-81 Abstract quote Three examples of cellular angiolipoma are presented. They occurred as part of multiple, occasionally painful, subcutaneous nodules on the extremities and trunk of healthy men. There was no familial tendency. Grossly, the cellular angiolipomas were small lesions, approximately 1 cm. Histologically, dense cellular angiomatous tissue comprised more than 95% of the lesions. Much of this component contained prominent spindle cells. Lesser degrees of involvement in the other subcutaneous nodules illustrated the continuum of histology between cellular angiolipomas and more typical angiolipomas. The differential diagnosis of cellular angiolipomas includes spindle cell lipoma, Kaposi's sarcoma, and other vascular tumors. The most important distinguishing features are encapsulation, intravascular fibrin thrombi, septation, association with other more typical angiolipomas, and occurrence in healthy individuals.
Hibernoma
The Morphologic Spectrum of Hibernoma A Clinicopathologic Study of 170 Cases Mary A. Furlong, M.D.; Julie C. Fanburg–Smith, M.D.; Markku Miettinen, M.D. From the Department of Soft Tissue Pathology, Armed Forces Institute of Pathology, Washington, DC, U.S.A.	Am J Surg Pathol 2001;25:809-814 Abstract quote Hibernoma, an uncommon tumor of brown fat, has been described only in a few case reports and small series. The authors reviewed 170 cases of hibernoma and evaluated the morphologic features and the behavior of this tumor. The records from the Soft Tissue Registry of the Armed Forces Institute of Pathology from 1970 were searched for cases coded as ``hibernoma.'' Clinical information and available slides from 170 hibernomas were reviewed. Immunohistochemical staining for S-100 and CD34 was performed on select cases. Follow-up information was obtained from the patients' medical records, the patients' physicians, and the patients themselves. Of 170 patients with hibernoma, 99 were men and 71 were women. The tumor occurred most commonly in adults, with a mean age of 38.0 years (age range, 2–75 years). Nine tumors occurred in pediatric patients. The most common anatomic locations included the thigh (n = 50), shoulder (n = 20), back (n = 17), neck (n = 16), chest (n = 11), arm (n = 11), and abdominal cavity/retroperitoneum (n = 10). The average duration of the tumor was 30.6 months. Tumor size ranged from 1 to 24 cm with an average dimension of 9.3 cm. All tumors were composed partly or principally of coarsely multivacuolated fat cells with small, central nuclei and no atypia. Four morphologic variants of hibernoma were identified: typical, myxoid, spindle cell, and lipoma-like. ``Typical'' hibernoma (n = 140) included eosinophilic cell, pale cell, and mixed cell types based on the tinctorial quality of the hibernoma cells. The myxoid variant (n = 14) contained a loose basophilic matrix. Spindle cell hibernoma (n = 4) had features of spindle cell lipoma and hibernoma; all occurred in the neck or scalp. The lipoma-like variant (n = 12) contained only scattered hibernoma cells. Immunohistochemically, 17 of 20 cases (85%) were positive for S-100 protein. Only one hibernoma of 20, a spindle cell variant, was positive for CD34, whereas other hibernoma variants were negative. Follow-up was obtained for 66 cases (39%) over a mean period of 7.7 years (range, 6 months–28 years). None of the patients with follow-up had a recurrence or metastasis, including eight with intramuscular tumors. No patient died of disease. Hibernoma is a tumor found most often in adults and most commonly in the thigh, with several morphologic variants. It is a benign tumor that does not recur with complete excision. Hibernomas should not be confused with atypical lipomas or well-differentiated liposarcoma.
Hibernoma. Lele SM, Chundru S, Chaljub G, Adegboyega P, Haque AK. Departments of Pathology (Drs Lele, Chundru, Adegboyega, and Haque) and Radiology (Dr Chaljub), University of Texas Medical Branch at Galveston, Galveston, Tex. Dr Lele is now at the Department of Pathology and Laboratory Medicine, University of Kentucky, Lexington.	Arch Pathol Lab Med 2002 Aug;126(8):975-978 Abstract quote Hibernomas are rare neoplasms composed of brown adipose tissue. The behavior of these neoplasms has been described as uniformly benign in humans. The only recurrence cited in the English literature involved a sarcoma with hibernoma-like features, which was reported in abstract form. We present 2 cases of hibernoma, one that continued to grow following partial excision and another at an unusual site (anterior abdominal wall). Both of these tumors overexpressed p53 protein by immunohistochemistry, which was a novel finding. A review of the literature highlights recent advances that may help confirm the diagnosis and explain the biology of these rare tumors.
Myelolipoma
Myelolipoma associated with adrenal ganglioneuroma. Merchant SH, Herman CM, Amin MB, Ro JY, Troncoso P. Department of Pathology, The University of Texas M. D. Anderson Cancer Center, Houston.	Arch Pathol Lab Med 2002 Jun;126(6):736-7 Abstract quote Adrenal myelolipomas are rare, benign mesenchymal tumors composed of mature adipose tissue and hematopoietic cells in varying proportions. Although the majority of cases occur as isolated adrenal lesions, myelolipomas have been described in association with various adrenal pathologic conditions. These conditions include enzyme deficiencies and hyperplastic and neoplastic lesions of the adrenal cortex, with perhaps endocrine dysfunction as a common feature. Ganglioneuroma is a benign tumor of the sympathetic nervous system that rarely produces symptoms of endocrine dysfunction. We report an unusual case of myelolipoma associated with ganglioneuroma of the adrenal medulla. The histogenesis of myelolipoma remains speculative. However, the close proximity to adrenal cortical cells within the stroma of ganglioneuroma suggests that the hormonal microenvironment may have played a role in the development of the myelolipoma.
Pleomorphic	Cancer 1981;47:126-133
Pleomorphic lipoma. Case reports and review of the literature. Digregorio F, Barr RJ, Fretzin DF. Department of Pathology, Humana Hospital-Michael Reese, Chicago, Illinois 60616-3390.	J Dermatol Surg Oncol 1992 Mar;18(3):197-202 Abstract quote Two patients are reported with pleomorphic lipoma, a benign subcutaneous fatty tumor showing atypia in which histologic diagnosis may be difficult. The tumors are well circumscribed lesions, most commonly occurring in the neck and shoulder of middle aged men. An important histologic criteria is the presence of floret-like multinucleated giant cells embedded in a myxoid stroma. Pleomorphic lipoma may be confused with several malignant soft-tissue neoplasms, including myxoid malignant fibrous histiocytoma and variants of liposarcoma. It is important to establish the correct diagnosis to avoid unnecessary radical surgery.
Spindle cell	Am J Dermatopathol 1995;17:529-533
Intradermal spindle cell/pleomorphic lipoma	Histopathology 1995;27:533-540 Am J Dermatopathol 2001;22:496-502 20 cases 20-85 years, median 42 years 14/20 females Sites: Head/neck, shoulder upper back, lower limbs, trunk, upper limbs Usually <2.5 cm Unencapsulated with poorly defined infiltrative margins, intradermal tumors, with occasional extension into subcutaneous tissue Variable portions of uniform short cells with scant to moderate amounts of eosinophilic poorly demarcated cytoplasm, small fusiform nuclei with vesicular chromatin, and indistinct nucleoli Mixed with pleomorphic cells with bizarre spindle cells and floret type giant cells May have prominent myxoid component Positive for CD34, negative for S100
Fibrous Spindle Cell Lipoma Report of A New Variant Carlos Diaz-Cascajo, etal.	Am J Dermatopathology 2001;23:112-115 Abstract quote Spindle cell lipoma is a benign tumor characterized by mature fatty tissue alternating with short fascicles of small spindle cells in a stroma that varies from fibrous to myxoid. The variable proportion of these elements among different examples of the neoplasm confers to spindle cell lipoma a variable microscopic appearance that can make the diagnosis difficult. Furthermore, in some instances, spindle cell lipoma may resemble liposarcoma, hemangiopericytoma, neurilemmoma, and other neoplasms representing a histopathologic pitfall. We report on two cases of spindle cell lipoma with abundant fibrous stroma reminiscence of fibroma and fibrolipoma. The name fibrous spindle lipoma is proposed for this tumor.

 

SPECIAL STAINS/IMMUNOPEROXIDASE/OTHER	CHARACTERIZATION
Special stains
Immunoperoxidase
CD34	J Cutan Pathol 1996;23:546-550 Positive in spindle cell lipomas
Leptin and Leptin Receptor mRNA are Widely Expressed in Tumors of Adipocytic Differentiation Andre M. Oliveira, M.D., Antonio G. Nascimento, M.D. and Ricardo V. Lloyd, M.D., Ph.D. Department of Laboratory Medicine and Pathology, Mayo Clinic and Mayo Foundation, Rochester, Minnesota Correspondence: Address reprint requests to: Ricardo V. Lloyd, M.D., Ph.D., Department of Laboratory Medicine and Pathology, Mayo Clinic	Mod Pathol 2001;14:549-555 Abstract quote Adipose tissue is the principal source of leptin, a cytokine-like peptide with many biologic functions. Leptin binds to the leptin receptor, present in the hypothalamus and in many other tissues, and modulates energy balance and maintenance of body weight. The expression of leptin and leptin receptor in tumors of adipocytic differentiation has not been previously examined. Because normal adipose tissue is the principal source of leptin and expresses leptin receptor, we hypothesized that tumors of adipose tissue differentiation may also express leptin and/or the long functional form of the leptin receptor (OB-Rb). Leptin and OB-Rb were analyzed by immunohistochemistry, in situ hybridization, RT-PCR, and western blotting in 21 lipomas, 2 hibernomas, and 16 liposarcomas. Immunostaining and in situ hybridization showed leptin and OB-Rb mRNA expression in all cases of lipomas, hibernomas, and liposarcomas, including dedifferentiated and pleomorphic liposarcomas. RT-PCR analysis showed leptin and OB-Rb mRNA in both lipomas (n = 5) and liposarcomas (n = 5). Western blotting identified the 16 kDa leptin protein in a lipoma and a liposarcoma. No important difference in the expression of leptin and OB-Rb mRNA was found between lipomas and liposarcomas, although the level of leptin protein was higher in a lipoma than a liposarcoma by western blotting. These results show for the first time that leptin and OB-Rb mRNA are expressed in lipomas, hibernomas, and liposarcomas. The presence of leptin and its receptor may provide new insights into the pathobiology of these tumors.

 

DIFFERENTIAL DIAGNOSIS	KEY DIFFERENTIATING FEATURES
LIPEDEMATOUS SCALP
Hyperplasia of the subcutaneous adipose tissue is the primary histopathologic abnormality in lipedematous scalp. Scheufler O, Kania NM, Heinrichs CM, Exner K.	Am J Dermatopathol. 2003 Jun;25(3):248-52. Abstract quote A 51-year-old white woman presented with thickening of the scalp located at the vertex and left lateral occiput without hair abnormalities or alopecia. Skin biopsies of the thickened scalp showed thickening of the subcutaneous tissue with proliferation of mature subcutaneous fat cells but no signs of inflammation or hair abnormalities. During 2.5 years of follow-up, scalp thickening progressed over the entire hair-bearing scalp and persisted without signs of further progression at 3.5 year follow-up. Lipedematous scalp is an extremely rare diagnosis. It is defined by a thickening of the subcutaneous layer of the scalp and can be distinguished from lipedematous alopecia, in which subcutaneous thickening is associated with diffuse alopecia and shortening of scalp hairs. A total of seven cases of lipedematous alopecia and two cases of lipedematous scalp have been reported. We report the third case of lipedematous scalp in a 51-year-old white woman associated with early symptoms of meningitis. Additional features described in the literature include pruritus, pain, and paresthesia of the scalp as well as associated medical problems such as hyperelasticity of skin and laxity of joints, renal failure, and diabetes mellitus. This sporadic disorder is predominantly located at the vertex and occiput. The etiology and pathogenesis of lipedematous scalp and alopecia remain unclear. The treatment is symptomatic.
LIPOSARCOMA	The chief differential is with cases of pleomorphic lipomas of the skin If lipoblasts are present in an otherwise typical pleomorphic lipoma of the skin, superficial, favor a diagnosis of pleomorphic lipoma

 

PROGNOSIS AND TREATMENT	CHARACTERIZATION
Prognostic Factors	Benign
Recurrence	1-2% in cases of intradermal spindle cell/pleomorphic lipomas
Treatment	Simple excision

Enzinger and Weiss's Soft Tissue Tumors. Fourth Edition. Mosby 2001.

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