Glomus Tumors



Glomus Tumors


Thomas Mentzel, MD










Clinical photograph shows a rare malignant glomus tumor.






Hematoxylin & eosin shows perivascularly arranged myogenic tumor cells that contain uniform round nuclei in a benign glomus tumor.


TERMINOLOGY


Abbreviations



  • Glomus tumor (GT)


Definitions



  • Perivascular myogenic mesenchymal neoplasm composed of cells closely resembling smooth muscle cells of normal glomus body


CLINICAL ISSUES


Epidemiology



  • Incidence



    • Rare


    • Account for < 2% of soft tissue neoplasms


  • Age



    • Predominantly occur in young adults


    • May occur at any age


  • Gender



    • No sex predilection


Site



  • Distal extremities


  • Often in subungual location


  • Rare in other anatomic locations (visceral organs, bone, mediastinum, nerve)


  • Skin, subcutis


  • Rare in deep soft tissue


Presentation



  • Typically small, red-blue nodules


  • Painful mass; long history of pain


  • Pain with exposure to cold &/or tactile stimulation


  • Usually solitary lesions


  • Rarely, may be multiple neoplasms


  • Multiple lesions more common in children


Natural History



  • < 10% recur locally


  • Malignant glomus tumors highly aggressive


  • Metastases and death of patients in up to 40% of cases


Treatment



  • Surgical approaches



    • Complete excision


Prognosis



  • Benign behavior in most cases


MACROSCOPIC FEATURES


General Features



  • Red-blue nodular lesions


MICROSCOPIC PATHOLOGY


Histologic Features



  • Perivascular myoid tumor cells


  • Small, uniform, round tumor cells


  • Centrally placed, sharply punched-out, round nuclei


  • Eosinophilic cytoplasm


  • Each cell surrounded by basal lamina


Predominant Pattern/Injury Type



  • Circumscribed


Predominant Cell/Compartment Type



  • Smooth muscle


Solid Glomus Tumor



  • Most common variant


  • Well-circumscribed nodular neoplasm


  • Contains numerous capillary-sized vessels


  • Nest of tumor cells surrounding capillaries


  • Stroma may show hyalinization


  • Stroma may show myxoid changes


  • Rare degenerative cytologic atypia


  • Rare vascular invasion may be identified


  • Peripheral rim of collagen (fibrous pseudocapsule)



  • May contain numerous hemangiopericytoma-like vessels


  • Rare oncocytic changes


  • Rare epithelioid variant


Glomangioma



  • Comprises up to 20% of glomus tumors


  • Most common type in patients with multiple lesions


  • Less well-circumscribed


  • Dilated veins surrounded by clusters of glomus cells


  • Secondary thrombosis may occur


Glomangiomyoma



  • Rare subtype


  • Solid glomus tumor or glomangioma with elongated, spindled smooth muscle cells


Glomangiomatosis



  • Extremely rare variant


  • Infiltrative growth


  • Multiple nodules of solid glomus tumor


  • Biologically benign lesions


Symplastic Glomus Tumor



  • Cells show prominent degenerative atypia


  • Multinucleated giant cells


  • Enlarged nuclei


  • No increased proliferative activity


  • No tumor necrosis

Jul 8, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Glomus Tumors
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