Pericytic (perivascular) tumors

Equal gender distribution for solitary and multiple lesions

Solitary lesions

• Wide age distribution

• Predominance in age groups between 20 and 40 years

Multiple lesions (in about 10%)

• Age of onset typically 10 to 15 years earlier than for solitary lesions

• Tend to occur predominantly in children

• Congenital occurrence also reported

• About two-thirds of the lesions develop by the age of 20 years

• Presentation in adults uncommon

• Nonhereditary or hereditary with autosomal-dominant inheritance with incomplete penetrance and variable expressivity

• Familial glomangiomas, also designated familial glomovenous malformations, have been found to be associated with mutations in the glomulin gene located on chromosome 1p21-22

Represents less than 2% of soft tissue tumors

The triad of symptoms, described by Masson in 1924

• Excruciating pain out of proportion to the size of the lesion

• Localized tenderness, reflected by positive Love sign (tenderness to a pinpoint spot with the end of the pencil)

• Temperature sensitivity, especially for cold, or changes in temperature, precipitating pain

Solitary lesions

• By far predominate (about 90%)

• Slowly growing papule or nodule with bluish discoloration, plaquelike presentation also reported

• Less than 1 cm in diameter

• Predilection for subungual areas of the finger, followed by palm, wrist, forearm, and foot

• Diverse extracutaneous sites, including gastrointestinal tract (esophagus, stomach, small bowel, colon), respiratory tract (trachea, lungs), mediastinum, bones, and peripheral nerves

Multiple lesions

• Small papules or nodules measuring usually from 0.1 to 0.3 cm and generally not exceeding 3 cm in diameter

• Plaquelike variant characterized by numerous reddish-blue papules grouped in a single or multiple plaques, and is frequently congenital

• Average number of lesions from 10 to 20

• Less often painful than solitary forms

• Lesions can become painful during the menstrual period or pregnancy, suggesting sensitivity to estrogens

• Association with diverse conditions has been reported, including multiple endocrine neoplasia (MEN) II syndrome, neurofibromatosis type I, arteriovenous (AV) fistulae, and brachydactyly

• Predilection for upper limbs

Benign clinical course

Complete surgical excision generally curative

Recurrences after incomplete/marginal excision from 5% to 50% and tend to be more common at subungual sites

Treatment in multiple lesions is directed toward symptomatic ones

Other treatment options include laser therapy and sclerotherapy

Classical or solid glomus tumor

• Well-demarcated, unencapsulated proliferation in the dermis/subcutis

• Nests and/or solid sheets of glomus cells

  • Round to oval, centrally located, uniform nuclei

  • Pale eosinophilic cytoplasm with well-defined borders

  • Mitoses absent or rare

  • Atypical mitoses absent

  • Rare variants consist of cells with epithelioid morphology

• Vascular component inconspicuous, usually in the form of thin-walled and frequently branching capillaries lined by flat endothelial cells

Glomangioma

• Less circumscribed, occasionally with infiltrative growth in the dermis/subcutis

• Vascular component prominent

• Dilated and congested vascular spaces, reminiscent of cavernous hemangioma, lined by a single layer of bland endothelial cells

• Thrombosis and organization of thrombi with formation of phleboliths not uncommon

• Glomus cells surround vascular spaces in a single or double layer, multilayering less common

Glomangiomyoma

• Smooth muscle cell component in addition to solid proliferation of glomus cells, the amount of the former component varies and is usually prominent

• Spindle cells arranged in bundles, fascicles, or display more irregular growth pattern

• Gradual transition from solid proliferation of glomus cells toward elongated smooth muscle cells (e.g., transitional zone) usually seen

Infiltrative glomus tumor

• Designation for glomus tumors with banal cytology, but infiltrative growth pattern

• Usually occurs in deep soft tissues

Additional histological features

• Stroma

  • Myxoid/collagenized

  • Can contain scattered nerves

  • Areas of calcification or bone formation uncommon

• Overlying epidermis generally unremarkable

Smooth muscle actin, muscle specific actin positive

Variable CD34 positivity

Desmin usually negative, focal positivity occasionally reported

MIR143 - NOTCH fusions are harbored in both benign and malignant glomus tumors, but not other myopericytic tumors; NOTCH 1 (9q34), NOTCH2 (1p31), and less commonly NOTCH3 (19p13.12) can be involved

Eccrine spiradenoma

Nodular hidradenoma

Vascular tumors

Vascular malformations