It is a neoplasm of the cells which resemble modified smooth muscle cells of glomus body
Normal glomus body is a specialized form at AV anastomosis that contains glomus cells which are scattered through out the muscle fibres. It serves for thermal regulation
Site – It is located in stratum reticularis of the dermis and frequently encountered in the subungual region, lateral areas of digits and the palm
Clinical features
Age – 20 – 40 years of age
Sex – Female predominance with male to female ratio of 3:1
Presentation –
small blue red nodules located in the deep dermis or subcutis of the upper and lower extremity
Common site – Subungual region of finger
other sites– palm, wrist, forearm and foot
Unusual sites – chest wall, bone, patella, colon, stomach, nerve, eyelid, nose, trachea and mediastinum, cervix, vagina, labia, and mesentry
Glomus coccygeum – Glomus tumor at the tip of spine
Patient presents with paroxysms of pain radiating away from lesion
pain is elicited by change in temperature (especially cold) and tactile sensation
Pain is associated with other findings like
hyperesthesia
Muscle atrophy
Osteoporosis of affected part
Autonomic dysfunction (or Horners syndrome)
Gross –
Small blue red nodules (usually <1cm)
Subungual lesions present as ridging of nail or discoloration of nail bed
Radiograph – if bone is involved it presents as scalloped osteolytic lesion with sclerotic border in the terminal phalynx
Microscopic findings
According to the proportion of Glomus cells, vascular structures and smooth muscle tissue, they have been divided into three groups
Glomus tumor proper
Glomangioma
Glomangiomyoma
These tumors vary in location
Glomus tumors are common in upper extremity with predilection for the finger, particularly subungual region
Glomangioma– more common in hand and forearm and are seen in familial cases with multiple lesions
Glomangiomyoma – they occur equally in both upper and lower extremity
Glomus tumor
Well circumscribed lesion composed of tight convolutes of capillary sized vessels surrounded by collars of glomus cells in hyalinized or myxoid stroma
Cells may be arranged in nests or appears as reminiscent of hemangiopericytoma, paraganglioma or a cellular appearance resembling epithelial tumor
Glomus cells has a rounded, regular shape with sharply punched out rounded nucleus setoff from the amphophilic or eosinophilic cytoplasm. Some cells have pale cytoplasm
Sometimes large hyperchromatic nuclei representing degenerative changes may be present
Periphery of the tumor have ill defined rim of collagen containing small nerves and vessels
Vascular invasion is rarely seen in benign glomus tumor
Glomangioma
less well circumscribed lesion constitutes 1/5th of cases
Lesion is composed of large gaping veins with small clusters of glomus cells in the walls
Secondary thrombosis or phlebolith may occur in this lesion
Glomangiomyoma
Constitutes less than 10% of all the glomus tumor
In these tumors there is gradual transition from glomus cells to elongated mature smooth muscle cells
Immunohistochemistry
Positive for Vimentin and muscle actin isoforms
Variably positive for Desmin
Differential diagnosis
Intradermal Nevi- lacks the intimate relation of tumor cells with small nests and lack of ductular differentiation
Treatment and prognosis
Treatment is surgical resection
Local recurrence occurs due to persistence of tumor following excision