Neurofibromatosis type 1 (NF1) is a common (~1/3000 birth incidence) disorder of increased tumor predisposition that arises secondary to mutations in the RAS-regulatory gene NF1
] Glomus tumors are rare, benign tumors of the glomus body that cause severe paroxysmal pain secondary to changes in temperature or pressure. Glomus tumors of the fingers and toes associated with NF1 [2
] arise due to bi-allelic inactivation of the NF1
] and are only recently recognized as part of the NF1 phenotype. [4
] They frequently appear as bluish subcutaneous nodules on the trunk and limbs and can be multi-focal. [6
] The first association of NF1 and glomus tumors was published in 1938. The report described a single 13-year-old girl with features consistent with NF1 and multiple soft, dark blue nodules on her right neck, bilateral lower extremities and left heel. A lesion from the right lower leg had histologic features consistent with a glomus tumor. [8
Glomus bodies are thermoregulatory shunts concentrated in the dermis of the fingertips and other peripheral sites subject to excessive cold and should be distinguished from unrelated adrenal and extra-adrenal paragangliomas, also commonly called “glomus tumors.” [10
] Glomus tumors of the fingers consist of a convoluted arterio-venous anastomosis surrounded by a thick layer of modified smooth muscle cells and nerve elements (). Glomus tumors are thought to arise from the modified smooth muscle cells of glomus bodies, although they can occur in regions where glomus bodies do not normally occur. [7
] Typically, a glomus tumor of the finger presents with a triad of localized tenderness, severe paroxysmal pain (out of proportion to size) and sensitivity to cold. They have a benign clinical course. [7
] However, glomus tumors of the fingers are under-recognized. One large series of sporadic glomus tumors of the fingers found that an average of 2.5 physicians (range 0–7), including psychiatrists, were consulted before the correct diagnosis was made. The duration of symptoms averaged 10 years (range 1– 40 years). [11
Figure 1 (A) Normal glomus body in the left F5 of patient NIH-1. Glomus bodies are thermoregulatory shunts that arise from arterio-venus anastomoses and are enveloped by condensed collagenous tissue. The vascular lumens are surrounded by several layers of modified (more ...)
Until recently, there were only eight cases of glomus tumors of the fingers and toes in individuals with NF1 in the English language literature (). [2
] There were no examples of multi-focal tumors in the largest retrospective review of 51 sporadic cases of glomus tumors of the fingers. [11
Summary of published accounts of glomus tumors of the fingers or toes in neurofibromatosis type 1.
In this report, we review the published literature and describe our multi-institutional experience (15 patients) with the presentation, diagnosis, imaging, management and complications of glomus tumors in the digits of individuals with NF1.