Glomus Tumor of the Scrotum: A Case Report

Glomus tumors are rare, usually benign, lesions that arise most often in the extremities. They are derived from the glomus body and have a propensity to be found in the ingers and toes, and often in the subungual area [1]. They typically demonstrate pinprick sensitivity, cold hypersensitivity and paroxysmal pain [2]. Only two glomus tumors of the scrotum have been reported and we report a third case of this rare tumor.


Introduction
Glomus tumors are rare, usually benign, lesions that arise most often in the extremities. They are derived from the glomus body and have a propensity to be found in the ingers and toes, and often in the subungual area [1]. They typically demonstrate pinprick sensitivity, cold hypersensitivity and paroxysmal pain [2]. Only two glomus tumors of the scrotum have been reported and we report a third case of this rare tumor.

Case Description
A 53-year-old man of Middle Eastern descent was referred by the dermatology service for evaluation and consideration of excision of a painful scrotal mass that had been present for about 10 months. Other than hypertension, he had no signi icant medical history. Physical examination revealed a small, non-in lamed subcutaneous nodule of the scrotum located just to the right of median raphe. The initial impression was a sebaceous cyst; however, it was extremely tender to palpation. After his initial visit, the lesion was removed under local anesthesia in our of ice.
Grossly, the mass was a well circumscribed, 1 cm in size, and tan in color. The histopathological indings were consistent with a glomus tumor: positive for SMA and vimentin, and negative for S-100 and CD-34.

Discussion
Glomus tumors are rare soft tissue neoplasms that are usually benign in nature 1 . They were irst clinically described in 1877, and Masson described the microscopic appearance in 1924 [3]. The tumors are most commonly found in peripheral soft tissues such as the ingernail and toes, as these are the locations where glomus bodies are most prominent. In rare circumstances, these have been described to be found within the airway and stomach 1 and in the urogenital tract, the glans penis, urethra, bladder and kidney [4,5].
Glomus bodies consist of myoarterial shunts which are physiologically involved in thermoregulation. They consist of an arteriole anastomosed with a venule and they are located within stratum reticularis of the dermis [6]. Diagnosis of a glomus tumor is primarily clinical; therefore, a thorough history and physical examination is paramount. Glomus tumors are most often bluish in hue, hypersensitive to cold temperatures, and exhibit local point tenderness. This tenderness can be demonstrated in the of ice using a Love's test, which is performed by using a pinhead or pencil tip to elicit an intense pain [7]. Treatment for a glomus tumor is primarily surgical, as no effective medical therapy exists [8] and diagnosis is con irmed on histopathology. Since they are derived from modi ied smooth muscle, glomus tumors stain positive for SMA, and vimentin, but do not stain for S-100 and CD-34 [9]. Due to their relative rarity, the follow-up of patients with glomus tumors is not well described. Tumor recurrence, while unusual, has been reported [10].
The differential diagnosis of a glomus tumor includes other perivascular tumors including myopericytoma, myo ibroma, and angioleiomyoma [11]. While these tumors may have overlap of their histopathological staining patterns, glomus tumors demonstrate a unique morphology of round cells exhibiting punched-out nuclei, pale cytoplasm, and a lacework of basement membrane material [6]. These pathological features are not demonstrated in the aforementioned tumors, and furthermore, glomus tumors are the only perivascular tumors found to be consistently painful in the clinical setting.
Of the now three reported cases of glomus tumor of the scrotum, each occurred in middle aged men [12,13]. This is the second case in a patient of Middle Eastern descent and, perhaps coincidentally, all three lesions were found to be in the right hemiscrotum. All tumors presented in relatively small size, being 1 cm or less. Our case included, no recurrence of these tumors has been reported.

Conclusion
Glomus tumors of the scrotum are rare entities; however, the diagnosis should be considered when a non-in lammatory super icial genital mass exhibits point tenderness and cold hypersensitivity. Treatment involves surgical excision, and diagnosis is con irmed on inal histopathology.