Photoletter to the editor: Collision tumor of melanoma and atypical fibroxanthoma of the scalp

Abstract

Several combinations of different skin tumors occuring one adjacent to the other or even in a single lesion have been described up to date. Collision tumors involving atypical fibroxanthoma and melanoma are extremely uncommon. Herein we present a case of melanoma associated with AFX and discuss on the usefulness of dermoscopy in the clinical diagnosis of collision tumors.

Keywords: collision tumor; dermoscopy; fibroxanthoma; melanoma; skin cancer; trichoscopy.

Figure 1

(a) Clinical aspect of a pigmented and an ulcerated nodule developing contiguously on the scalp. (b) Dermoscopy of the pigmented nodule revealed irregular blotches, irregular globules, a blue-white veil and remnants of pigment network at the periphery, overall suggestive of melanoma. (c) A large ulceration, whitish-pinkish areas and a polymorphous vascular pattern dermoscopically characterized the non-pigmented nodule.

Figure 2

(a) Melanoma. Histopathologic examination reveals a dermal-based proliferation of atypical pigmented melanocytes on a background of severely damaged skin. The inflammatory infiltrate and the superficial erosion in the left upper corner are the residual sign of the previous punch biopsy. (b) Melanoma cells at higher magnification. (c) Atypical fibroxanthoma. On histology, the dermis is diffusely infiltrated by a richly cellular neoplasm. (d) At higher magnification, it is composed of pleomorphic and mitotically active spindle cells. (e) The neoplastic cells are diffusely immunoreactive with CD68.