myxoid dermatofibrosarcoma protuberans
The myxoid variant of dermatofibrosarcoma protuberans (DFSPs) is uncommon. It is defined as a DFSP with greater than 50% myxoid stroma.
Synnopsis
sex ratio 1/1
median age 40 years (range 9 months to 72 years)
tumor size: from 1.5 to 11 cm (median 2.8 cm)
most frequent sites: extremities, head and neck, trunk, anogenital region
Gross: white/tan/gray to yellow, firm to gelatinous soft tissue masses
tumor stroma: from 50 to 100% myxoid (median 80%)
infiltrative sheet-like proliferation of bland spindle cells with palely eosinophilic cytoplasm
stellate nuclei without pleomorphism
stroma myxoid with prominent thin-walled vessels
honeycomb infiltration of fat
cellular areas more typical of DFSP
+/- pigmented dendritic cells (Bednar variant)
+/- areas of giant cell fibroblastoma
rare progression to fibrosarcomatous DFSP
Mitoses: from 0 to 5 per 10 high power fields
Immunochemistry
CD34 + (95%)
S100 -
muscle markers -
Prognosis
local recurrence
no metastasis
See also
myxoid tumors
References
Reimann JD, Fletcher CD. Myxoid dermatofibrosarcoma protuberans: a rare variant analyzed in a series of 23 cases. Am J Surg Pathol. 2007 Sep;31(9):1371-7. PMID: #17721193#