PURPOSE: Orbital pleomorphic lipoma has been rarely reported in the literature. Although floretlike cells are characteristic of pleomorphic lipoma, they are not pathognomonic. We reviewed cases of prolapsed orbital fat and exenteration specimens to determine the significance of presence of these cells in the diagnosis of orbital pleomorphic lipoma. DESIGN: Retrospective interventional case series with clinicopathologic correlation. PARTICIPANTS: Seventy-two specimens of 45 patients with prolapsed orbital fat and 74 exenteration specimens as controls. INTERVENTION: Histologic review of the specimens including light microscopy, Masson trichrome staining, immunostaining for S100, CD34, CD68, terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) assay, and transmission electron microscopy and review of clinical records and analysis of the data with generalized estimation equation. MAIN OUTCOME MEASURE: Evidence of histologic abnormalities in histologic specimens and clinical and demographic data. RESULTS: Floretlike cells were present in 31 of 72 (43%) specimens of prolapsed orbital fat and in 12 of 74 (16%) orbital exenterations. Fewer than 6 florets were present in twenty 40x high-power fields in 15 (48%), 6 to 10 in 9 (29%), and >10 in 7 (23%) specimens. The florets stained positive for CD34 but not for S100 or CD68. TUNEL assay revealed significant nuclear pyknosis, and transmission electron microscopy disclosed spindle-shaped cells with abundant rough endoplasmic reticulum and no basement membrane. The mean age of patients with prolapsed orbital fat with florets was 67 years (range, 52-86). Of 31 samples, 29 (94%) were from males. Of 30 samples, 29 (97%) were located in the superotemporal conjunctiva; only one was located in the lower lid. There was significant association between the presence of florets and location of the prolapsed orbital fat (P = 0.0013) and gender (P = 0.0015). CONCLUSION: Floretlike cells may be present in in situ and prolapsed orbital fat as a degenerative process. What some have called "orbital pleomorphic lipoma" is in fact only age-related orbital fat prolapse.

Pleomorphic lipoma: a definite histopathological entity.Anticancer Res. 2004 Sep-Oct;24(5B):3157-9.

Pleomorphic lipomas are rare benign tumours that can resemble a variety of malignant tissue tumour on histological examination. We describe a case of pleomorphic lipoma arising on the posterior aspect of the neck of a 70-year-old man, successfully treated by surgical excision. A review of the literature is presented, summarizing the principal clinical and morphological characteristics of this rare tumor.

Pleomorphic lipoma: case report and literature review.Dermatol Surg. 2000 Apr;26(4):375-80.

BACKGROUND: Pleomorphic lipoma is a rare, benign, pseudosarcomatous, soft tissue neoplasm typically involving the subcutis of the neck and shoulder in middle-aged to elderly men. It is characterized histologically by atypical, multinucleated giant cells and grossly as a well-circumscribed mass. Since this neoplasm can resemble a sarcoma, histopathologic diagnosis is critical in preventing unnecessary surgery. OBJECTIVE: To describe a case of pleomorphic lipoma in the neck and to review the clinical and histopathologic characteristics of this neoplasm. METHODS: We present a case report and review of the literature. RESULTS: Local excision to completely extirpate this neoplasm has proven curative at 10 months of follow-up. CONCLUSION: Pleomorphic lipoma is superficially located and may be encountered in a dermatologic setting. Thus the dermatologist should become familiar with its clinical presentation and microscopic appearance.