Author: A/Prof Patrick Emanuel, Dermatopathologist, Auckland, New Zealand, 2013.
Tumours of the follicular infundibulum are rare, arise in the head and neck, and clinically resemble superficial basal cell carcinoma. Rarely, there are multiple tumours, when they have been associated with Cowden disease. They are also known as “follicular infundibulum tumour” or “infundibuloma”.
Histology of tumour of the follicular infundibulum
In tumour of the follicular infundibulum, sections show an acanthoma composed of pale pink cells and sometimes clear cells. The tumour forms anastomosing narrow strands that run parallel to the epidermis. These strands have peripheral palisading of basaloid cells (figures 1, 2).
Special studies of tumour of the follicular infundibulum
None are generally needed.
Differential diagnosis of tumour of the follicular infundibulum
Basal cell carcinoma – Though both tumours show peripheral palisading, the tumour cells of tumour of the follicular infundibulum are pale pink or glycogenated rather than basaloid throughout. Anastamosing thin strands running parallel to the epidermis are generally not seen or only focally seen in basal cell carcinoma
Pathology of the Skin (Fourth edition, 2012). McKee PH, J. Calonje JE, Granter SR