Myxoid dermatofibroma on a great toe: a case report.
Dermatofibroma is a common benign fibrohistiocytic tumor with many clinicopathological variants. Myxoid dermatofibroma is one of these variants, which is characterized by marked stromal mucin deposition. This report presents a case of myxoid dermatofibroma on a great toe that had been slowly growing for two years. Histopathologically, the relatively well-circumscribed dermal tumor was separated from the epidermis by a small grenz zone. The tumor tissue consisted of oval to spindle-shaped cells with well-defined cell borders and spindly condensed nuclei. No cytologic atypia or mitotic figures were found. Although most of the tumor cells were embedded in a prominently myxoid stroma, typical features of classic dermatofibroma including a storiform growth pattern and more densely packed collagen were observed at the periphery. Immunohistochemically, the tumor cells showed positive staining for CD68 and CD99, and negative staining for CD34 and S-100. Histopathological differential diagnoses of myxoid dermatofibroma include soft tissue neoplasms with myxoid tumor stroma, such as superficial acral fibromyxoma, cellular digital fibroma, superficial angiomyxoma, myxoid dermatofibrosarcoma protuberans and low-grade fibromyxoid sarcoma. Immunohistochemical staining can be useful in the differential diagnosis of these tumors. This case highlights the challenges encountered in the histopathological interpretation of myxoid dermatofibroma. Pathologists should keep in mind the diagnosis of myxoid dermatofibroma when dealing with myxoid neoplastic lesions arising on acral sites.
Department of Pathology, Soonchunhyang University Bucheon Hospital, Soonchunhyang University College of Medicine Bucheon-si, Gyounggi-do, Republic of Korea.
Ahrim
A
Moon
Department of Pathology and Translational Genomics, Samsung Medical Center, Sungkyunkwan University School of Medicine Seoul, Republic of Korea.
Nara
N
Yoon
Department of Pathology, Severance Hospital, Yonsei University College of Medicine Seoul, Republic of Korea.
Hyun-Soo
HS
Kim
D014408:Biomarkers, Tumor / Q000032:analysis; D001706:Biopsy; D003937:Diagnosis, Differential; D005260:Female; D018219:Histiocytoma, Benign Fibrous / Q000737:chemistry / Q000473:pathology* / Q000601:surgery; D006801:Humans; D007150:Immunohistochemistry; D008875:Middle Aged; D011237:Predictive Value of Tests; D012878:Skin Neoplasms / Q000737:chemistry / Q000473:pathology* / Q000601:surgery; D014034:Toes / Q000473:pathology* / Q000601:surgery; D016896:Treatment Outcome; D047368:Tumor Burden
D014408:Biomarkers, Tumor
Dermatofibroma; immunohistochemistry; myxoid variant; superficial acral fibromyxoma