Congenital hamartoma of the scalp with meningothelial, sebaceus, muscular, and immature glandular components

A 4-month-old boy presented with a congenital, solitary, yellowish-red, eroded tumor on the scalp, histologically characterized by an ectopic proliferation of vascular and meningothelial elements intimately admixed with mature connective-tissue elements, adipose tissue, and smooth-muscular fibers. In addition, the presence of characteristic histopathological features of a nevus sebaceus and areas with immature glandular differentiation were observed. The diagnosis of a congenital hamartoma of the scalp with meningothelial, sebaceus, immature glandular, and muscular components was established. We review the heterogeneous group of cutaneous lesions with meningothelial elements and their pathogenesis.