Dermatofibrosarcoma Protuberans.

Sir,

A 42-year-old woman presented with history of multiple asymptomatic progressive nodular lesions over abdomen since 8 years. Patient had small nodular lesion at the same site, which was excised 9 years back. On cutaneous examination, multiple erythematous nodules of variable sizes were coalescing to form a large plaque over the abdomen [Figure 1]. A large solitary erythematous protuberant nodule measuring 10 × 8 cm was present over the plaque. Scaling and crusting were noticed over larger lesion. On palpation it was firm, non-tender, and not freely mobile over the underlying structures. There was no regional lymphadenopathy. On investigation, her complete blood count, liver function tests, and renal function tests were within normal limit. Serological tests for human immunodeficiency virus (HIV) and hepatitis B were negative. An incisional biopsy was performed under local anesthesia and tissue was sent for histopathology. Hematoxylin and eosin (H and E) stain showed spindle shaped tumor cells arranged in storiform pattern in the dermis [Figure 2]. Immunohistochemical (IHC) study showed positive for human progenitor cell Ag CD34 [Figure 3] and vimentin and negative for S100 protein, features suggestive of dermatofibrosarcoma protuberans (DFSP).

Figure 1

Multinodular mass with protuberant lesion over abdomen

Figure 2

Histopathology showing spindle shape tumor cells in dermis (H and E, ×10)

Figure 3

Immunohistochemistry showing positivity to CD34 (IHC, ×40)

DFSP is a locally aggressive, low grade, and relatively uncommon cutaneous neoplasm which has a high propensity for local relapse with low metastatic potential.[12] It accounts for <0.1% of all neoplasms, with an annual reported incidence of 0.8–4.5 cases per million.[34] It is most commonly seen in third or fourth decade with slight male preponderance.[5] Trunk is the most common site affected followed by proximal extremities and scalp. Head and neck, and genitals are rarely involved.[6] Clinically, it presents as pink or violet red plaque which may be surrounded by telangiectatic skin.[7] These lesions are fixed to skin, but move freely over underlying structures. They do not exhibit nodular growth pattern until late in their course. It becomes fixed to underlying structures in advanced and/or recurrent cases.[8] Clinically, it may be confused with other conditions such as sclerosing basal cell carcinoma, morphea, scar, and anetoderma.[89] On histopathology, it shows spindle-shaped neoplastic cells arranged in cartwheel or storiform pattern in the dermis.[7] Immunohistochemical stains are employed to differentiate DFSP from dermatofibroma, as sometimes it is difficult to differentiate the two on routine H and E stain. Studies have shown that CD-34 and vimentin are usually expressed in many cases of DFSP. Coagulation factor XIIIa is generally not expressed in DFSP, but is strongly expressed in dermatofibroma.[10] In our case it showed positive for both CD34 and vimentin. Surgical excision is the treatment of choice. Due to the high recurrence rate, radical excision is the preferred option. It involves complete surgical excision of the tumor with wide margins (>3 cm).[7] Mohs micrographic surgery is the most precise margin controlled approach for excision of DFSP.[11]

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Conflicts of interest

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