Derm Dx: Dome-shaped erythematous nodule on the scalp
A patient, aged 67 years, requested an evaluation of an enlarged lesion on his mid scalp. The lesion was first noted four weeks prior to presentation. The growth was asymptomatic and the patient denied associated itching, burning or bleeding. The patient was fair skinned and admitted to ample sun exposure over many decades.
Past medical history was positive for multiple actinic keratosis as well as for skin cancer. Three years ago, he received radiation therapy to a basal cell carcinoma located on his frontal scalp.
Examination revealed a dome-shaped erythematous nodule. A biopsy was performed.
Submit your diagnosis to see full explanation.
Atypical fibroxanthoma is an uncommon spindle celled neoplasm that develops within actinically damaged skin or areas of radiation dermatitis in elderly individuals.1 The head and neck are the most common sites and the tumor occurs with greatest frequency in white males.
Atypical fibroxanthoma classically presents as a rapidly growing, solitary asymptomatic nodule that may ulcerate or bleed. Typically, they are smaller than 2 cm in diameter but can range from 0.3 cm to 10 cm.
Clinical differential diagnosis includes basal and squamous cell carcinomas as well as pyogenic granuloma and amelanotic melanoma.2,3
While the etiology of atypical fibroxanthomas is unknown, p53 mutations induced by ultraviolet (UV) radiation seems to play a role in the pathogenesis. 4 The occurrence of this skin cancer in transplant patients suggests immune dysregulation as another proposed cause of this condition.5
Definitive diagnosis is made by biopsy which reveals a densely cellular nodule with pleomorphic spindle and giant cells containing scattered mitoses and atypical forms.6
Early literature describes atypical fibroxanthomas as benign lesions with prognosis described as excellent.7 Several subsequent case reports, however, document a rare potential for metastatic spread and mortality. 8,9
Although multiple modalities have been used to treat this neoplasm — including electrocautery, radiation therapy and cryotherapy — the potential for local recurrence and even distant spread warrant wider excision with demonstration of clear margins.1
Megha D. Patel, is a student at the Commonwealth Medical College, Scranton, Pennsylvania.
Stephen Schleicher, MD, is an associate professor of Medicine at the Commonwealth Medical College and an Adjunct Assistant Professor of Dermatology at the University of Pennsylvania Medical College. He practices dermatology in Hazleton, Pennsylvania.
- Iorizzo LJ, Brown MD. Dermatol Surg. 2011; doi: 10.1111/j.1524-4725.2010.01843.x
- Goette DK, Odom RB. Arch Dermatol. 1976;112:1155-7
- Diaz-Cascajo C, Weyers W, Borghi S. Am J Dermatopathol. 2003;25:1-5
- Dei Tos AP, Maestro R, Doglioni C, et al. Am J Pathol. 1994;145:11-7
- Paquet P, Pierard GE. Dermatology. 1996;192:411-3
- Elder D. (1997.) Tumors of fibrous tissue. Lever’s Histopathology of Skin. (8th ed.) Philadelphia, PA: Lipponcott.
- Starink TH, Hausman R, Van Delden L, Neering H. Br J Dermatol. 1977;97:167-77
- Helwig EB, May D. Cancer 1986; 57:368-76
- Cooper JZ, Newman SR, Scott GA, Brown MD. Dermatol Surg. 2005; 31:221- 225