[Glomus tumor of subungual presentation in the thumb and use of ultrasound in its diagnosis. Case report and literature review].

Introduction: the glomus tumor is a benign neoplasm originated in the smooth muscle cells of the vascular glomus. Approximately 80% of lesions are located on the upper extremity and, of these, the majority are in the subungual area. The diagnosis must include imaging tests, among which ultrasound stands out, being a good alternative due to its low cost and accessibility.

Objective: we present a case of late diagnosis of surgically managed glomus tumor, as well as a review of the existing literature for diagnosis, treatment, and prognosis of this uncommon pathology.

Clinical case: the case of a 52-year-old female patient who reported chronic, burning pain, radiating to the distal phalanx of the thumb with no history of trauma, of 2 years of evolution and which limited her daily life activities, is presented. The exploration with interphalangeal Doppler ultrasound is complemented, being an excellent alternative due to its easy accessibility. A glomus tumor was diagnosed in the interphalangeal thumb. An "H" approach was performed on the interphalangeal fold with subungual dissection with resection of the tumor piece and follow-up by an outpatient clinic where a surgical wound with adequate healing was found. Physical examination with capacity for the mobilization of the distal interphalangeal joint (IFJ) and visual analogue scale (VAS) 1 point. The updated pathological evaluation of the existence of a glomus tumor.

Conclusions: ultrasound is an excellent aid in the diagnosis, as well as in the surgical planning for the treatment of the glomus tumor; for being accessible, low cost and highly effective. The anatomopathological study is the gold standard.