Kransdorf MJ, Meis JM: From the archives of the AFIP: extraskeletal osseous and cartilaginous tumors of the extremities. Radiographics 13: 853, 1993.
Alves JV, Matos DM, Barreiros HF, et al: Variants of dermatofibroma: a histopathological study. An Bras Dermatol 89: 472, 2014.
Han TY, Chang HS, Lee JH, et al: A clinical and histopathological study of 122 cases of dermatofibroma (benign fibrous histiocytoma). Ann Dermatol 23: 185, 2011.
Kelati A, Aqil N, Baybay H, et al: Beyond classic dermoscopic patterns of dermatofibromas: a prospective research study. J Med Case Rep 11: 266, 2017.
Juliandri J, Wang XY, Liu ZJ, et al: Dermoscopic patterns of dermatofibroma in 72 chinese patients. Chin Med J (Engl) 132: 2121, 2019.
Arouni MA, Bewtra C, Albano WA, et al: Atypical, cutaneous fibrous histiocytoma with early metastasis. Nebr Med J 71: 126, 1986.
Moosavi C, Jha P, Fanburg-Smith JC: An update on plexiform fibrohistiocytic tumor and addition of 66 new cases from the Armed Forces Institute of Pathology, in honor of franz m. Enzinger, md. Ann Diagn Pathol 11: 313, 2007.
Gu M, Sohn K, Kim D, et al: Metastasizing dermatofibroma in lung. Ann Diagn Pathol 11: 64, 2007.
Wollina U, Schönlebe J, Nowak A: Cellular fibrous dermatofibroma of the sole. Georgian Med News 256-257: 11, 2016.
Hattori T, Matsumine A, Uchida K, et al: Benign fibrous histiocytoma of the talus: a case report. J Foot Ankle Surg 58: 762, 2019.
Moon A, Yoon N, Kim HS: Myxoid dermatofibroma on a great toe: a case report. Int J Clin Exp Pathol 8: 7605, 2015.
Lehmer LM, Ragsdale BD: Digital dermatofibromas—common lesion, uncommon location: a series of 26 cases and review of the literature. Dermatol Online J 17: 2, 2011.
Gleason BC, Fletcher CD: Deep “benign” fibrous histiocytoma: clinicopathologic analysis of 69 cases of a rare tumor indicating occasional metastatic potential. Am J Surg Pathol 32: 354, 2008.
Lin CM, Huang HL, Chu FY, et al: Association between gastroenterological malignancy and diabetes mellitus and anti-diabetic therapy: a nationwide, population-based cohort study. PLoS One 10: e0125421, 2015.
Wojciechowska J, Krajewski W, Bolanowski M, et al: Diabetes and cancer: a review of current knowledge. Exp Clin Endocrinol Diabetes 124 (5): 263, 2016.
Vrachnis N, Iavazzo C, Iliodromiti Z, et al: Diabetes mellitus and gynecologic cancer: molecular mechanisms, epidemiological, clinical and prognostic perspectives. Arch Gynecol Obstet 293: 239, 2016.
Hussin P, Loke SC, Noor FM, et al: Malignant melanoma of the foot in patients with diabetes mellitus: a trap for the unwary. Med J Malaysia 67: 422, 2012.
Gao W, Chen D, Ran X: Malignant melanoma misdiagnosed as diabetic foot ulcer: a case report. Medicine (Baltimore) 96: e7541, 2017.
Yasear ZAY, Bloomer L, Siddique R, et al: When acral malignant melanoma facades as diabetic foot! BMJ Case Rep 14: e242918, 2021.
Hao X, Yim J, Chang S, et al: Acral lentiginous melanoma of foot and ankle: a clinicopathological study of 7 cases. Anticancer Res 39: 6175, 2019.
Hao X, Billings SD, Wu F, et al: Dermatofibrosarcoma protuberans: update on the diagnosis and treatment. J Clin Med 9: 1752, 2020.
Wu KK: Malignant fibrous histiocytoma of the foot. J Foot Surg 29: 298, 1990.
Stanoszek LM, Wang GY, Harms PW: Histologic mimics of basal cell carcinoma. Arch Pathol Lab Med 141: 1490, 2017.
Rupp M, Khalluf E, Toker C: Subungual fibrous histiocytoma mimicking melanoma. JAPMA 77: 141, 1987.
Gaufin M, Michaelis T, Duffy K: Cellular dermatofibroma: clinicopathologic review of 218 cases of cellular dermatofibroma to determine the clinical recurrence rate. Dermatol Surg 45: 1359, 2019.
Background: Dermatofibroma (DF) is a common benign soft-tissue tumor. It occurs anywhere on the body but is commonly seen on the upper and lower extremities. It is frequently found in young to middle-aged adults and predominantly in females.
Methods: Thirty-one patients with DF on the foot and ankle diagnosed and treated during a 6-year period were characterized.
Results: The patients (16 males, 15 females) were aged 7 to 75 years (average, 55 years). Clinically, 17 patients noted painful symptoms, and 14 were painless. Grossly, DF manifested as a raised red, pink, tan, or skin-colored soft mass. The tumor size ranged from 0.3 to 1.5 cm (average, 0.67 cm in diameter). Twenty-six DFs (84%) were localized on the dorsal surface of the foot and ankle, and five (16%) were found on the plantar aspect. Eighteen patients were treated by surgical excision of the tumor (>0.5 cm), and 13 patients had observational follow-up after punch biopsy due to the small size (≤0.5 cm) and benign nature of these lesions. Further follow-up found that only one patient (3.2%) had a local recurrence, 37 months after surgical excision, which was completely reexcised. Histologically, DF is characterized by proliferation of spindle fibroblasts and histiocytes, in a vague fascicular pattern, and thickened collagen bundles.
Conclusions: Dermatofibroma on the foot and ankle predominantly occurs in patients in their 50s, without a preponderance by sex. It needs to be differentiated from other benign and malignant tumors with histologic analysis and immunostaining with factor XIIIa, CD68, and other biomarkers. Treatment options include either surgical excision or observational follow-up after biopsy, depending on the clinical characteristics and effect on functional activity.