Case report 820: Granular cell tumor of striated muscle

Intramuscular granular cell tumor: emphasizing the stripe sign

We present a case of an intramuscular granular cell tumor in the thigh manifesting a 'stripe sign' on magnetic resonance imaging (MRI). This MR finding may correspond with the entrapped muscle fibers within the tumor, which demonstrated parallel arrangement on histopathologic examination. In addition, other disease entities characterized by the presence of this sign such as proliferative myositis, heterotopic ossification, and muscular sarcoidosis will be reviewed.

Case report. Granular cell tumors of extremities: comparison of benign and malignant variants

Granular cell tumors are uncommon soft tissue neoplasms that arise from cells of neural origin. We present three patients with this rare tumor: one with a benign tumor, one with a malignant tumor, and one with a histologically benign tumor that later metastasized to the lung. We studied the difficulty in differentiating between the benign and malignant variants using only histology. We also compared the clinical, radiographic, and pathologic features and the criteria for malignancy, natural history, and prognosis.

Granular cell tumor of the extremity: magnetic resonance imaging characteristics with pathologic correlation

OBJECTIVE

The purpose of this study is to delineate the magnetic resonance (MR) appearance of a granular cell tumor (GrCT) of the extremity and to correlate the imaging appearance with the microscopic findings.

DESIGN AND PATIENTS

A retrospective review of five patients with a histopathologic diagnosis of GrCT and pre-operative MR imaging of the neoplasm was done. The images were reviewed by two musculoskeletal radiologists in a consensus fashion. Lesion location, size, shape, margination, and signal intensity characteristics were assessed. MR findings were correlated with histopathological examination.

RESULTS

The benign subtype of GrCT is usually isointense or brighter than muscle on T1-weighted sequences, round or oval in shape, superficial in location, and 4 cm or less in size. On T2-weighted sequences, benign lesions may demonstrate a high peripheral signal, as well as a central signal intensity that is isointense to muscle or suppressed fat. A significant stromal component in the tumor and, hypothetically, a ribbon-like arrangement of tumor cells may influence the signal intensity demonstrated on the T1 and T2-weighted sequences. The malignant subtype may demonstrate signal intensity characteristics and invasion of adjacent structures often seen with other aggressive neoplasms; sizes larger than 4 cm and association with major nerve trunks can be seen.

CONCLUSION

Benign GrCT has imaging characteristics which may distinguish this tumor from other soft tissue neoplasms, as well as the malignant type of this tumor.

Granular cell tumors of the extremities

Granular cell tumors are uncommon tumors that may arise from various soft tissue and visceral sites. These lesions often are multifocal but, with rare exceptions, are benign. Much of the literature on granular cell tumors is based on case reports mostly in the otolaryngology literature, and most series are limited to histopathologic studies. There are no documented series of cases in the orthopaedic literature. Granular cell tumors do occur in the extremities; thus, patients with a peripheral granular cell tumor may be referred to an orthopaedist. Ten cases of benign granular cell tumor treated at the authors' institution between 1993 and 1999 are reported. Five tumors of the thigh and one tumor of the groin were treated with wide excision, whereas three tumors of the hand and one tumor of the elbow were treated with marginal resection. Although two tumors treated with attempted wide excision had positive margins, none of the tumors have recurred after an average followup of 27 months. The presentation, radiography, histologic findings, and treatment of benign granular cell tumors that distinguish it from other soft tissue lesions are discussed.

Granular cell tumor of the hypopharynx treated by endoscopic CO(2) laser excision: report of two cases

BACKGROUND

Granular cell tumor (GCT), or Abrikossoff's tumor, is an unusual lesion probably arising from Schwann cells. It is frequently found in the head and neck region, where the tongue is the most commonly affected site. Involvement of the hypopharynx is exceedingly rare because, to the best of our knowledge, only four cases have been reported in the literature.

METHODS

We describe hypopharyngeal GCT in two women aged 29 and 52 years, respectively.

RESULTS

In the first patient, preoperative diagnostic examination, including endoscopy, CT, and MRI scan, was suggestive of a benign lesion arising from the posterior wall of the hypopharynx. In the second patient, a previous biopsy of the postcricoid area performed elsewhere suggested a diagnosis of well-differentiated squamous cell carcinoma, and CT scan staged the lesion as T1 N0. In both cases, treatment included surgical excision under microlaryngoscopy with CO(2) laser. The histopathologic study of the specimens, supported by immunohistochemical techniques, determined the lesions to be a GCT. The postoperative course was uneventful, and the patients were discharged 12 and 2 days after surgery, respectively. Both patients were asymptomatic without evidence of recurrence when last seen 2 years and 4 months after surgery, respectively.

CONCLUSIONS

GCT should be included in the differential diagnosis of submucosal hypopharyngeal lesions. Endoscopy and radiologic imaging do not display any typical finding suggestive of the diagnosis, which can be based only on histologic findings. Resection of the tumor, when technically feasible, should be performed under microlaryngoscopy with the CO(2) laser, which makes it possible to work in a bloodless field with minimal thermal damage and reduction of scarring and postoperative edema.