Granular cell tumor: a rare tumor of the ulnar nerve

Case report: Giant atypical granular cell tumor of the median nerve

Granular cell tumors are extremely uncommon soft tissue neoplasms that mostly occur in the head and neck regions. Granular cell tumors are generally benign, asymptomatic, and rarely involve the median nerve. Due to the lack of awareness about granular cell tumors, they are easily misdiagnosed and mistreated in primary hospitals. Here, we report a giant atypical granular cell tumor located on the median nerve, approximately 12 cm in size, with unusual symptoms of median nerve damage. Magnetic resonance imaging revealed a fusiform mass that was hyperintense on T2-weighted images and iso-hypointense on T1-weighted images. The mass was subsequently biopsied and found to be a granular cell tumor. The tumor was resected, and a pathological examination was performed. Pathological examination revealed necrotic foci, abundant eosinophilic granules, pustular ovoid bodies, and multiple mitoses. Immunohistochemical staining revealed that the tumor cells were positive for S-100, CD68, SMA, SOX-10, Calretinin, and TFE3. The integrated diagnosis was an atypical granular cell tumor. To the best of our knowledge, this is the first report of an atypical granular cell tumor involving the median nerve. Furthermore, we comprehensively reviewed the existing literature to provide a concise summary of the diagnostic criteria, imaging findings, and pathological features of granular cell tumors. Given the high recurrence and metastasis rates of this disease, granular cell tumors of the median nerve should be considered when a patient presents with symptoms of median nerve impairment. The diagnosis of atypical granular cell tumors relies on pathological examination. In addition, extensive resection and long-term follow-up are necessary to improve prognosis.

[Granular cells tumour (Abrikossof) of the ulnar nerve at the arm. A case report and literature review]

INTRODUCTION

Granular cell tumours are extremely rare on peripheral nerves, with an incidence of 0.029% of pathologic samples. In a literature review, we found only 5 cases involving the ulnar nerve, although considered the most frequently involvement nerve.

CASE REPORT

A 32 year-old female from the French West Indies presented a severe arm pain with deficit of interosseous hand muscles. Imaging studies were in favour of a Schwanoma, but during surgery, we found an unremovable intra-neural tumour. Nerve biopsy revealed a granular cell tumour. Initial decision was observation only. However, within two years, tumour increased in size, along with pain aggravation and functional deficit. We performed a nerve resection (with adequate margins) with reconstruction using sural nerve graft associated with a neurotisation of the motor branch with the anterior interosseus nerve. At two years follow-up, no recurrence was observed. The scar is hypersensitive with moderate neuropathic pain. There is a sensory reinnervation of the fourth finger, with no motor recovery of the hand. We observed a slight recovery of flexor profundus tendons, which, in turn increased the claw hand.

DISCUSSION

The five cases described in the literature were managed differently (biopsy only, excision, excision with reconstruction), with modest results. There is no recommended treatment. Our case is the first at arm level. We were able to perform complete resection, but functional result is poor.

CONCLUSION

Granular cell tumours require treatment if symptomatic (pain, function loss), but, at the moment, there is no recommended treatment.

Benign peripheral nerve tumors

Benign peripheral nerve tumors encompass a wide range of neoplasms and non-neoplastic tumor like lesions. Some of these lesions if not encountered in the setting of genetic syndromes, are occurring sporadically. The principles of oncology should be respectfully followed in every step of diagnostic approach and surgical management. Albeit, classified as benign, some of them do have different level of malignant potential, thus the treating physicians should be aware of that to avoid possible pitfalls with devastating outcomes. This article reviews the most common benign peripheral nerve tumors discussing the clinicopathological findings, imaging appearance and the current trend in their approach.

Granular cell tumor on the palm of an 8-year-old girl

Granular cell tumors are rare benign peripheral nerve neoplasms that are most commonly reported on the tongue and oral mucosa. Rarely, they can present as masses on the extremities. They are often treated surgically, however, guidelines for the optimal surgical management of these lesions have yet to be defined. We report a child with a granular cell tumor of the palm that required removal by an orthopedic hand surgeon.

Intramuscular granular cell tumor in the lower extremities

Granular cell tumors are uncommon but typically histologically benign neoplasms that occasionally behave as malignant tumors. Differentiation of benign granular cell tumors from malignant counterparts with radiographic and/or histologic analysis is crucial for physicians. We retrospectively studied five cases of intramuscular granular cell tumors arising in the lower extremities. All tumors had been histologically diagnosed as benign and were resected with a wide surgical margin. The minimum followup was 1 year (mean, 45 months; range, 12-119 months) after surgery. Four patients had no local recurrence or distant metastasis (at a minimum of 18 months followup), whereas one patient with lymph node metastasis had a recurrence and distant metastasis 3 months after surgery resulting in death. Intramuscular granular cell tumors can be diagnosed based on their characteristic MRI features, such as peripheral high intensity on T2-weighed images, and histologic evaluation. The histologic criteria described by Fanburg-Smith et al. can differentiate malignant granular cell tumors from benign tumors. A wide resection seems suitable for most granular cell tumors in the extremities.

LEVEL OF EVIDENCE

Level IV, diagnostic study. See the Guidelines for Authors for a complete description of evidence.

Granular cell nerve tumor in the hand: case report

Granular cell tumor of a digital nerve is extremely rare; I could identify only 2 previous reports in the literature. I present a case of a granular cell tumor arising from an index digital nerve that was treated with wide resection and nerve graft reconstruction.