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Case 393 - Discussion

Uploaded: 2010-05-11, Updated: 2010-05-11

 

SMA

Glomus Tumor

The Key Features

  • Common location: subungual areas of fingers;

  • Paroxysmal pain;

  • SMA positive.

CLINICAL FEATURES

  • Origin: glomus cell, a modified smooth muscle cell in the glomus body (Sucquet-Hoyer canal) which regulates temperature;

  • Incidence, 1.6% of soft tissue tumor in US;

  • Age: 20-40 year-old;

  • Usually F=M, but in subungual lesions, F:M = 3:1;

  • Paroxysmal pain, which can be severe and exacerbated by pressure or temperature changes, especially cold;

  • Two useful tests:

    • Hildreth sign: disappearance of pain after application of a tourniquet proximally on the arm;

    • Love test: eliciting pain by applying pressure to a precise area with the tip of a pencil.

GROSS FINDINGS

  • Small, <1.0 cm, blue or purple papules or nodules, can be blanched;

  • Most commonly in the upper extremities, especially subungual areas of fingers.

MICROSCOPIC FINDINGS

  • Solid well-circumscribed nodules surrounded by a dense fibrous pseudocapsule;

  • Tumor cells in solid sheets, organoid or epithelioid pattern; interrupted by vessels in variable sizes; hyalinized or myxoid background;

  • Tumor cells are monomorphous round or polygonal with sharply round nuclei and scant to moderate, eosinophilic or amphophilic cytoplasm.

SUBTYPES

  • Solitary glomus tumors

  • multiple variant

DIFFERENTIAL DIAGNOSES

  • Angioleiomyoma

  • Angiolipoma

  • Arteriovenous (AV) malformations

  • Congenital plaquelike blue nevus

  • Hemangioma

  • Melanoma

  • Spiradenoma

  • Tufted angioma

IMMUNOHISTOCHEMISTRY AND SPECIAL STAINS

  • SMA: positive

  • Cytokeratin: negative

  • S100: negative

TREATMENT AND PROGNOSIS

  • Surgical excision

REFERENCES

  • http://www.emedicine.com/derm/topic167.htm

  • Enzinger and Weiss's Soft Tissue Tumors, 5th Edition. By Drs. Sharon Weiss and John Goldblum. 2007