REPORT OF A CASE
A 63-year-old man presented with a large nodule on his scalp. He reported the lesion to be present for 30 years; the lesion developed as an asymptomatic papule in a site of trauma. The lesion had slowly enlarged and recently ulcerated.On physical examination, a 5.5×5.0-cm ulcerated tumor draining purulent exudate was seen on the vertex of the scalp (Figure 1). There were hyperkeratotic columns and scale-crust on the surface of the tumor. No cervical or occipital lymphadenopathy was noted.An incisional biopsy and subsequent excision of the tumor with graft placement was performed (Figure 2 through Figure 4).What is your diagnosis?
Proliferating trichilemmal cyst (PTC).
Compact hyperkeratosis and areas of scale-crust were seen. An intradermal tumor composed of lobulated, well-circumscribed squamous epithelium was seen extending to the subcutaneous fat. The lobules had a basaloid
Bulengo-Ransby SM, Johnson C, Metcalf JS. Enlarging Scalp Nodule. Arch Dermatol. 1995;131(6):724. doi:10.1001/archderm.1995.01690180101020