Glomus Tumor Within the Tensor Fascia Lata: A Case Report

Background

Glomus tumors are rare, benign, soft-tissue lesions, representing around 1% to 2% of all soft-tissue tumors. Most glomus tumors occur in the hand, especially in the subungual region, as it is rich in blood vessels. Glomus tumors can occur in other regions of the body, and this is considered a very rare situation. The usual clinical presentations consist of pain, tenderness at the site of the tumor, and hypersensitivity to cold. Most of the time, extradigital glomus tumors are difficult to diagnose, and symptoms can persist for a long time. A few similar cases for glomus tumors around the knee region have been reported with similar presentation. Transformation to a malignant tumor is rare. However, a deeper location and larger size could have a role in this malignant transformation. We report a case of an extradigital glomus tumor of the left proximal thigh. The diagnosis was confirmed by histopathology [1–6].

Case Report

A 39-year-old man was referred to our institute for evaluation of a continuous stabbing pain in his left thigh associated with paresthesia, and hypersensitivity to cold and clothes. The pain was exacerbated with activity, particularly going up and down stairs, playing football, and running. The pain also became more intense while stretching after waking up. The pain started 3 years ago, and had been gradually increasing since that time. Physical examination showed a mild, limp, non-palpable mass, severe tenderness on palpation on the lateral upper thigh, and no signs of infection or skin changes. The plain radiographs were unremarkable. Magnetic resonance imaging (MRI) with contrast was performed and showed a well-defined intramuscular lesion in the tensor fascia lata, isointense in T1 as well as high signal intensity in T2 via weighted and STIR imaging. It was around 9×9 mm in size (Figures 1–3). Then, a percutaneous biopsy was done through ultrasound guidance for diagnostic purposes. Ultrasound imaging revealed a round, solid, hypoechoic, homogeneous mass in the left upper thigh (Figure 4). Histopathology revealed that the tumor cells were round in shape, with indistinct borders and a rounded, sharply punched-out nucleus in the amophilic to eosinophilic cytoplasm. No evidence of atypia, necrosis, the spindling of cells or malignancy was seen (Figure 5). Immunohistochemistry showed positivity with vimentin, SMA, muscle-specific actin, and Caldesmon. After that, the patient was scheduled for surgical excision. Under general anesthesia, the patient was positioned in the lateral decubitus position on the operating table. A longitudinal skin incision was made along the biopsy entry point. This was followed by dissection of subcutaneous tissues focused and directed toward the biopsy tract until the lesion was identified within the tensor fascia lata (Figure 6). Finally, a marginal excision of the mass was performed. The patient was seen in the clinic 2 weeks later and the symptoms had resolved completely. Informed patient consent was signed for publication purposes.

Discussion

Wood was the first to report glomus tumors, in 1812, describing them as “painful subcutaneous tubercles”, followed by Masson, who termed them glomus tumors in 1924 [2,3,7]. Glomus tumors are derived from the glomus body, a thermo-regulatory structure that regulates blood circulation to adjacent skin [1]. The classical triad presentations are pain, tenderness, and sensitivity to cold.

Generally, the hand is the commonly seen affected site. However, occurrence in the gastrointestinal tract, mediastinum, trachea, mesentery, bone, cervix, and vagina is also possible but less common [8]. Diagnosis is always challenging for physicians, particularly given that the mass is deep and non-palpable, but it can be accurately identified through precise history and clinical examination followed by appropriate investigations. Although a glomus tumor is a benign neoplasm, malignant glomus tumors must be identified if the tumor arises in a deep area and is larger than 2 cm in size [9]. In our case, the tumor was non-palpable, and imaging revealed that the tumor was deep under the skin and within the tensor fascia lata. Percutaneous biopsy was performed initially to confirm the diagnosis and to rule out malignant features such as nuclear atypia, necrosis, or mitotic activity [1].

Conclusions

Glomus tumor of the thigh is a rare neoplasm, especially in the proximal thigh; it is difficult to diagnose and is associated with morbidity. Diagnosis can be made through a systematic approach and simple investigation, such as via ultrasonography. A percutaneous biopsy can help in drawing up a management plan, and malignancy must be considered if the lesion is suspicious. Symptoms can persist in case of incomplete re-section or unrecognized synchronous satellite lesions; thus, symptomatic neuroma should be considered [8].