Benign tumors
Glomus Tumor
Definition
- •
A benign tumor composed of modified smooth muscle cells (e.g., glomus cells)
- •
Subclassified into three groups based on the proportions of glomus cells, blood vessels, and (perivascular) smooth muscle cells into:
- •
Classical or solid glomus tumor
- •
Predominance of glomus cells
- •
Blood vessels small and nondistinctive
- •
- •
Glomangioma
- •
Blood vessels are prominent and dilated
- •
Represents the most common variant
- •
- •
Glomangiomyoma
- •
Prominent smooth muscle component
- •
The rarest subtype
- •
- •
- •
Pattern of presentation/occurrence
- •
Solitary or multiple (localized, plaquelike, disseminated) lesions
- •
Sporadically or in the familial setting with autosomal-dominant inheritance pattern
- •
Acquired or congenital
- •
- •
Multiple tumors generally correspond to glomangioma on histology
Clinical features
Epidemiology
- •
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
Presentation
- •
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
- •
Prognosis and treatment
- •
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
Pathology
Histology
- •
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
- •
Immunohistochemistry/special stains
- •
Smooth muscle actin, muscle specific actin positive
- •
Variable CD34 positivity
- •
Desmin usually negative, focal positivity occasionally reported
Genetic profile
- •
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
Main differential diagnoses
- •
Eccrine spiradenoma
- •
Nodular hidradenoma
- •
Vascular tumors
- •
Vascular malformations
Classical (solid) glomus tumor
Glomangioma
Glomangiomyoma
Symplastic Glomus Tumor
Definition
- •
A very pale histological variant of glomus tumor displaying areas of cytological atypia and nuclear pleomorphism, not associated with malignancy
- •
Nuclear atypia likely degenerative phenomenon and/or related to cellular senescence, with DNA methylation possibly involved in the pathogenesis of the symplastic change
Clinical features
Epidemiology
- •
Female predominance (F : M = 3 : 1)
- •
Wide age distribution (from 16 to 83 years), most common in the fifth decade
Presentation
- •
Slowly growing, tender or painful nodule
- •
Pain can be triggered by cold exposure
- •
Subungual lesions can be associated with nail deformities
- •
Size less than 1 cm in diameter
- •
Predilection for fingers, particularly subungual site
Prognosis and treatment
- •
Complete local excision generally curative
- •
Recurrences rare (up to 13%), usually after incomplete/marginal excision, less likely due to synchronous satellite lesions
Pathology
Histology
- •
Nonencapsulated, well-demarcated proliferation in the dermis, with possible extension into the subcutis
- •
Areas of classical glomus tumor usually present at the periphery of the proliferation (see earlier)
- •
Defining histological feature is polygonal tumor cells with pronounced cytological atypia (e.g., symplastic change), but lacking other features of malignancy
- •
Nuclei large and pleomorphic, frequently hyperlobated and bizarre shaped with hyperchromasia, intranuclear cytoplasmic pseudoinclusions, coarse chromatin, and irregular nuclear membrane
- •
Mitotic activity generally absent
- •
Necrosis absent
- •
Pale eosinophilic cytoplasm with indistinct cellular borders
- •
Immunohistochemistry/special stains
- •
Smooth muscle actin and CD34 positive
- •
Desmin, S100 protein, cytokeratin, CD31, and factor XIIIa negative
- •
Ki-67/MIB-1 negative or very low (less than 1% of the tumor cells)
Glomangiomatosis
Definition
- •
Glomangiomatosis is defined as angiomatosis associated with a prominent glomus cell component
Clinical features
Epidemiology
- •
Most common in the third decade of life
- •
Slightly more common in females
- •
Very rare, with fewer than 20 cases reported
Presentation
- •
Solitary slowly growing nodule, measuring from 1.5 cm to over 20 cm
- •
Lesions at deeper locations (e.g., paravertebral soft tissues) generally larger and more extensive
- •
Sites of involvement include lower and upper extremities, head and neck, and chest wall, whereas no lesions reported at subungual site
- •
Excruciating pain common
Prognosis and treatment
- •
Difficult to remove completely due to the infiltrative growth
- •
Surgery represents the primary treatment modality
- •
Completeness of excision the most important prognostic parameter for local recurrence(s)
- •
Local recurrences in 60%, multiple recurrences in 20%
Pathology
Histology
- •
Infiltrative growth pattern typical, with skeletal muscle involvement in over 50%
- •
Two main components are glomus cells and large dilated vascular spaces
- •
Glomus cells
- •
Clusters, sheets, or nodules surrounding and infiltrating anomalous vessel walls
- •
Bland cytology (see glomus tumor )
- •
- •
Angiomatosis
- •
An admixture of blood vessels of different size and caliber
- •
- •
Mature fat occasionally represents significant component of the lesion
Immunohistochemistry/special stains
- •
Glomus cells
- •
Smooth muscle actin and muscle specific actin positive
- •
Variable CD34 positivity
- •
Desmin usually negative
- •
Main differential diagnoses
- •
Glomangioma (distinguish by clinical presentation)
- •
Vascular malformation
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
