An Unusual Presentation of Dermatofibroma with Ulcer: A Case Report.

Dermatofibroma is a common mesenchymal skin lesion that typically presents as a firm, slow-growing nodule. Generally, such lesions are asymptomatic; however, they can also cause discomfort in some cases. Ulceration is an uncommon feature of dermatofibroma, and diagnosis in such cases is often difficult. We report a case of a 67-year-old female with multiple comorbidities, including pancreatic cancer undergoing neoadjuvant chemotherapy, who was admitted for acute pulmonary embolism. The patient presented with an incidental medial thigh lesion. The lesion was asymptomatic, ulcerated, and oozing pus one month before presentation. Clinical examination revealed a 3 × 2 cm deep ulcer with a punched-out edge, a dry yellow-white base, and a firm violaceous border. Histopathology confirmed dermatofibroma with epidermal hyperplasia, dermal spindle cell proliferation, histiocytes, and collagen trapping. Immunohistochemistry was positive for CD68, CD10, and Factor XIII. Due to the deteriorating condition of the patient, no intervention was provided to her, and she succumbed to her primary illness. This case is unique due to its atypical ulcerative presentation in a patient with complex systemic illness and emphasizes distinguishing between benign lesions and malignant mimics, especially in cases which have ambiguous clinical presentation.