An 81-year-old fair-skinned woman was referred for evaluation of a growth on her scalp. The patient is suffering from dementia and a caretaker relates that the lesion is frequently traumatized during hair combing and bleeds. Review of her medical history reveals prior treatments for squamous cell carcinomas and actinic keratoses. On physical examination, a crusted papule on a base of dried blood is noted on the scalp. Occipital and cervical lymph nodes are not palpable.
Submit your diagnosis to see full explanation.
Atypical fibroxanthoma (AFX) is a rare, low-grade sarcoma.1 Sun exposure is believed to play a role in the development of the disease and most lesions appear on sun-exposed skin such as the scalp, forehead, ears, and nose. Other risk factors include trauma, radiation therapy, and immunosuppression. The disease affects men and women equally and the average age at the time of diagnosis is approximately 70 years.2
A typical AFX lesion is an erythematous to pink solitary nodule or plaque. Over time lesions will grow to 2 cm to 3 cm; multiple lesions are uncommon. On dermoscopy, AFX can resemble other skin cancers such as basal cell carcinoma, squamous cell carcinoma, and amelanotic melanoma, and definitive diagnosis is based on skin biopsy.3 Histopathology of the lesion reveals a nonencapsulated dermal tumor comprised of spindle-shaped pleomorphic cells.
The mainstay of AFX therapy is surgical excision with Mohs surgery.4,5 Recurrence is most apt to occur in immunosuppressed patients.
Sara Mahmood, DPM, is a podiatrist who completed a joint dermatology/podiatry fellowship and is on staff at DermDox Dermatology Centers. Stephen Schleicher, MD, is director of the DermDox Dermatology Centers, associate professor of medicine at Commonwealth Medical College, and clinical instructor of dermatology at Arcadia University and Kings College.
1. López L, Vélez R. Atypical fibroxanthoma. Arch Pathol Lab Med. 2016;140(4):376-379. doi:10.5858/arpa.2014-0495-RS
2. Soleymani T, Aasi SZ, Novoa R, Hollmig ST. Atypical fibroxanthoma and pleomorphic dermal sarcoma: updates on classification and management. Dermatol Clin. 2019;37(3):253-259. doi:10.1016/j.det.2019.02.001
3. Cichewicz AW, Białecka A, Męcińska-Jundziłł K, et al. Atypical fibroxanthoma mimicking amelanotic melanoma in dermoscopy. Postepy Dermatol Alergol. 2019;36(4):492-494. doi:10.5114/ada.2019.87453
4. Tolkachjov SN, Kelley BF, Alahdab F, Erwin PJ, Brewer JD. Atypical fibroxanthoma: systematic review and meta-analysis of treatment with Mohs micrographic surgery or excision. J Am Acad Dermatol. 2018;79(5):929-934.e6. doi:10.1016/j.jaad.2018.06.048
5. Jibbe A, Worley B, Miller CH, Alam M. Surgical excision margins for fibrohistiocytic tumors, including atypical fibroxanthoma and undifferentiated pleomorphic sarcoma: A probability model based on a systematic review. J Am Acad Dermatol. 2021;S0190-9622 (21)02519-6. doi:10.1016/j.jaad.2021.09.036