Rapidly Evolving Giant Dermatofibroma

Abstract

Dermatofibroma, also known as “fibrous histiocytoma”, is a benign dermal or subcutaneous poorly circumscribed proliferation of spindle-shaped fibroblasts and macrophages in the dermis. Although it is commonly present as a brownish nodule the legs of females, it may also arise on the upper extremities, trunk, and rarely on the head. The exact pathogenesis is unclear. However, it is widely believed that the originating insult to the dermis is a folliculitis, an arthropod bite, or an unspecified initial inflammatory condition. Giant dermatofibromas of greater than 5 cm in diameter are rare, with only 22 cases reported in the literature. We present a case of a rapidly evolving pedunculated mass in the groin of a male patient. Histological examination confirmed this to be a giant dermatofibroma. Though this specimen cannot is not confirmed as such, the cellular subtype is sometimes present as a larger lesion with anecdotal reports of local recurrence and distant metastases. The clinical and radiological features which were somewhat suspicious of malignancy are considered in the context of the definitive pathological diagnosis of a benign lesion.

An asymptomatic nodule on the upper thigh

“…Giant dermatofibroma typically displays conventional histopathology with no evidence of atypia. Interestingly, in our patient, the histological features were those of a cellular dermatofibroma, a variant associated with an increased tendency to local recurrence (approximately 25%), 4 and infrequently, metastasis. The cellular variant of dermatofibroma is infrequently seen (5%) but more commonly encountered in larger lesions 5 .…”

Giant Muscle Invasive Dermatofibroma Clinically Mimicking a Malignant Tumor

“…The differential diagnoses of dermatofibromas include other benign lesions such as nodular fasciitis, neurofibromas, and leiomyomas, as well as malignant tumors such as DFSP [5]. On immunostaining, dermatofibromas typically test negative for the CD 34 antibody (positive in 85% of DFSP) and positive for SMA, CD 68, and factor XIIIa [9]. In the case described, the immunohistochemical reactions were suggestive of a dermatofibroma, and mitoses were not conspicuous; Ki 67 labeling index was also low, suggestive of a benign tumor such as dermatofibroma.…”

Plaque like giant dermatofibroma: A case report

“…Cellular dermatofibroma is a rare pathological subtype representing <5% of all fibrous histiocytomas. [ 5 ] This pathological variant while still favouring the lower limbs, is more common in males and most are <2 cm in diameter. When very large, the lesions may present clinically as a giant dermatofibroma.…”