Melanocytic lesions associated with dermatofibromas: a spectrum of lesions ranging from junctional nevus to malignant melanoma in situ

Abstract

Dermatofibromas are common lesions that are often associated with epidermal hyperplasia and basal layer hyperpigmentation. A single case of lentiginous melanocytic hyperplasia overlying a dermatofibroma has been reported, however, nevi and melanoma have to the best of our knowledge, not been previously reported. We present 14 cases of melanocytic lesions associated with dermatofibromas. The clinical data and hematoxylinand eosin-stained sections were obtained and formalin-fixed, paraffin-embedded tissue was immunostained with antibodies against S-100, Mart-1, Factor XIIIa, and CD117. There were nine females and five males ranging in age from 30 to 64 years and anatomic sites included back (five), arm (six), flank (two), and leg (one). The clinical diagnosis ranged from dermatofibroma to desmoplastic melanoma. Histologically, the melanocytic lesions included junctional, compound, and dermal nevi, and malignant melanoma in situ. In four cases the dermal component appeared to merge with the dermatofibroma. In the case of the melanoma in situ, the dermatofibroma abutted the epidermis. Immunohistochemically, the melanocytic lesions were S-100/ Mart-1 þ , FXIIIa-, and the dermatofibromas were S-100/Mart-1À, FXIIIa þ . Melanocytic neoplasia may appear in association with dermatofibromas. The fibrohistiocytic proliferation may be misinterpreted as a spindle or pleomorphic melanocytic process. Awareness of this association will aid in the correct diagnosis, and immunohistochemical studies will help in the differentiation of these two cell populations.

CD34+ Pigmented Fibrous Proliferations: The Morphologic Overlap Between Pigmented Dermatofibromas and Bednar Tumors

“…Although they have pigmented dermal dendritic melanocytes, they also demonstrate basal cell hyperpigmentation and one of the cases even had an incipient melanocytic nest (case 1). This finding has been described in dermatofibromas 12 but not, to our knowledge, in DFSP. In addition, the lesions are not deeply placed with extensive involvement of the subcutis; they abut the fat, similar to many cellular dermatofibromas with a deep component.…”

Nonmelanocytic Lesions Defying the Two-Step Dermoscopy Algorithm

“…13 Furthermore, the association of melanocytic lesions ranging from lentiginous melanocytic hyperplasia to melanoma in situ overlying or merging with a DF has also been described. 14…”

Inflammation drives wound hyperpigmentation in zebrafish by recruiting pigment cells to sites of tissue damage

“…This is commonly observed in minor inflammatory conditions such as acne but can also be seen in fibrotic wounds and lesions (Halder and Nootheti, 2003; Cayce et al, 2004; King et al, 2005; Coley and Alexis, 2009). This wound-associated pigment disorder is most apparent in people with a dark complexion, but also occurs in people with pale skin (Halder and Nootheti, 2003; Coley and Alexis, 2009); currently, however, little is known about the cells and molecular signals that might drive wound hyperpigmentation.…”