Glomus tumor of the coccyx
A glomus tumor of the coccyx is a rare benign neoplasm with the same morphologic features, expressed by glomangiomas occurring at extracoccygeal sites as under the fingernails or toes.
It seems to be a rather rarely described entity with only a few cases described in the literature 1-3.
Benign glomangiomas are expansile, well-circumscribed vascular lesions, which can erode the bone surface. Their size is usually up to 1-2 cm in dimension 1,2 and thus larger as the usual size of the glomus coccygeum, which is reported 1-5 mm 2. Similar to the glomus coccygeum, coccygeal glomus tumors seem to be located in the soft tissue immediately ventral or below to the tip of the coccyx near the anococcygeal ligament 1-3.
The macroscopic appearance of coccygeal glomus tumors is that of a well-circumscribed nodular lesion 1,2.
Microscopically they consist of small arterioles, surrounded by several layers of modified smooth muscle cells.
Glomus cells usually express smooth muscle actin, vimentin and neuron-specific enolase 1,2.
Glomus tumors of the coccyx are usually quite small and will usually not be noticed on plain radiographs.
There are no reports about the appearance of coccygeal glomangiomas in the literature. However, it should look like an ovoid well-circumscribed lesion with soft tissue density, with possible bone erosion ref.
A report describes a glomus tumor of the coccyx as an ovoid lesion with well-circumscribed margins 1:
- T1: hypointense
- T2: hyperintense
- T1 C+ (Gd): homogeneous avid enhancement
The radiological report should include a description of the following:
- location, size and signal characteristics of the lesion
- form, margins and transition zone
- bony erosions
- any other abnormalities of the coccyx and the sacrum as well as the pelvic floor, which might be a source for the patient's pain or symptoms
Treatment and prognosis
In case of longstanding otherwise non-explained coccygodynia, it can be excised.
History and etymology
The glomus coccygeum was first identified by Hubert von Luschka 5 (1820-1875), who compared it to the glomus caroticum. Its vascular origin was first recognized by Julius Arnold (1835-1915), but it was not until 1942 when William H. Hollinshead established physiological and anatomical discriminations between the coccygeal glomus tumor and the glomus caroticum.
Coccygeal glomus tumors have been reported by Nutz and Stelzner 3, Llombart 4 and Kim 1.
The differential diagnosis of coccygeal glomus tumors includes the following 2:
- glomus coccygeum: smaller, frequent should not cause cold sensitivity or tenderness
- paraganglion or paraganglioma
- neuroendocrine tumors
Apparently glomus tumors of the coccyx represent a significant challenge for most pathologists 2, therefore it might be advisable to point out the suspected diagnosis in the radiological report.
- 1. Kim HS, Yang SH, Park HJ, Park HB, Cho HS. Glomus tumor as a cause of coccydynia. (2013) Skeletal radiology. 42 (10): 1471-3. doi:10.1007/s00256-013-1654-z - Pubmed
- 2. Bisceglia M, Bisceglia S, Ciampi C, Panniello G, Galliani C. Glomus coccygeum: a review. (2018) Pathologica. 110 (4): 287-293. Pubmed
- 3. Nutz V, Stelzner F. [Glomus tumor as a cause of coccygodynia]. (1985) Der Chirurg; Zeitschrift fur alle Gebiete der operativen Medizen. 56 (4): 243-6. Pubmed
- 4. Llombart A, Fernandez AL, Peydro A. [Coccygeal localization of neuro-pericytial glomangioma]. (1969) Annales d'anatomie pathologique. 14 (3): 327-34. Pubmed