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Spindle
Cell/Pleomorphic Lipoma |
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CLINICAL FEATURES |
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Mostly in men 45-60 years of age,
in the subcutaneous tissue of the posterior neck, shoulder and
back.
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Typically slowly growing, solitary,
painless, firm nodule.
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GROSS FINDINGS |
- Well circumscribed, soft
yellow, with focal gray-white gelatinous areas, of increased
cellularity.
- Some tumors show extensive myxoid changes or lipomatous
changes.
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MICROSCOPIC FINDINGS |
- Typically a mixture of mature
fat and spindle cells.
- The spindle cells
- Arranged haphazardly, but tend to arranged in short,
parallel bundles, often with nuclear palisading.
- Are uniform with a single elongated nucleus and narrow,
bipolar cytoplasmic processes. Nucleoli and mitoses are
inconspicuous.
- Background with mucoid material and collagen fibers.
- Tumor may show predominant spindle cells or mature fat.
- Mast cells in all cases.
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IMMUNOPROFILE |
- CD34+, S100+ in mature fat,
BCL2+, SMA-
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CYTOGENETIC STUDIES |
- Del(16q) or
del(13q)
- Lack of giant
marker and ring chromosomes.
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DIFFERENTIAL DIAGNOSES |
- DFSP: storiform, no fat tissue.
- Nodular fasciitis: more variable appearance, SMA+, CD34-.
- Solitary fibrous tumor:
patternless pattern,
thin collagen fibers, no prominent adipose, CD99+, BCL2+, CD34-.
- Atypical/well differentiated
liposarcoma: deep soft tissue of abdomen and extremities,
pleomorphic lipoblasts, giant marker and ring chromosomes.
- Pleomorphic liposarcoma: extremitis, pleomorphic lipoblasts,
metastasis.
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TREATMENT AND PROGNOSIS |
- Completely benign lesion.
Rarely recurs, even if incompletely excised.
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REFERENCES: Enzinger and Weiss's Soft Tissue
Tumors, 5th Edition. By Drs. Sharon Weiss and John Goldblum.
2007 |