Question 6 of 16

(demo test)

The images and histopathology associated with this question demonstrate a glomus tumor.

A glomus tumor is a benign solitary blue-red subungual circumscribed tender papule. They are derived from the modified smooth muscle cells that line the Sucquet-Hoyer canal (an arteriovenous fistula) that is involved in regulation of temperature of the fingers and toes (Gombos et al. Arch Pathol Lab Med 2008). They are most commonly located in the subungual regions of the upper extremity and foot. Patients often complain of significant pain with pressure or temperature change.

Histopathology of glomus tumors demonstrates well-circumscribed blood vessel proliferations which are surrounded by round, monotonous, densely packed cells with a round nucleus and abundant pink cytoplasm (glomus cells) in a myxoid pale dermis. These cells often demonstrate “single-filing.” Lesions may be surrounded by a dense fibrous pseudocapsule. Glomus cells stain positive for smooth muscle actin and desmin.

Treatment is with excision, electrodesiccation, or sclerotherapy (Chou et al. Ann Plast Surg 2016). MRI and CT show strong enhancement of glomus tumors and may be useful in surgical planning.

Meissner’s corpuscles are mechanoreceptors located in the dermal papillae of digital skin and are responsible for touch and light pressure sensation.

Pacinian corpuscles (Vater-Pacini) are located within the deep dermis and subcutaneous tissue and are responsible for the sensation of vibration.

An eccrine spiradenoma is also a blue tumor that can be painful. The basaloid cells within an eccrine spiradenoma are similar to glomus cells, however, the basaloid cells line eccrine sweat ducts rather than vessels.

Clinical Pearl: Glomus tumors are benign solitary blue-red subungual circumscribed tender papules derived from modified smooth muscle cells that line the Sucquet-Hoyer canal. Histopathology demonstrates well-circumscribed blood vessel proliferations surrounded by glomus cells.