SECTION EDITOR: MARY S. STONE, MD; ASSISTANT SECTION EDITORS: SOON BAHRAMI, MD; CARRIE ANN R. CUSACK, MD; MOLLY A. HINSHAW, MD; ARNI K. KRISTJANSSON, MD; LORI D. PROK, MD
Histopathologic examination revealed a polypoid nodular lesion involving the dermis and subcutis with small incidental reactive nodes (Figure 2). It consisted of banal spindled and stellate stromal cells within abundant vascularized myxoid stroma, sprinkled with neutrophils (some appear eosinophil-like with bilobed nuclei) (Figure 3). A keratinizing epithelial cyst was centered in the lesion. The lesion was negative for S100 protein.
Superficial angiomyxoma is a rare, benign tumor. It was first described in 1988 as an entity that is histologically similar to the cutaneous myxomas of Carney complex but without evidence of the complex.1 Superficial angiomyxomas are typically solitary, smaller than 5 cm in diameter, more common in men, and affect all ages but most commonly occur in the third and fourth decades of life, although congenital superficial angiomyxomas have been reported.2,3 They typically occur on the head, neck, and trunk but can arise on lower extremities and genitals.3,4 If present on the external ear, they are almost pathognomonic for Carney complex.5 Local recurrence following excision of superficial angiomyxomas occurs in 30% to 40% of patients.1
Exophytic Nodule on the Scalp—Diagnosis. JAMA Dermatol. 2013;149(6):751-756. doi:10.1001/jamadermatol.2013.3314g