Tumour of the follicular infundibulum pathology

Introduction

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).

Figure 1 

Figure 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