Granular cell tumor of colon: a case report

CASE REPORT

Granular cell tumor of colon: a case report

Eduardo Brambilla^I; Marcos Antonio Dal Ponte^II; Henrique Rasia Bosi^III; Rodrigo Paese Capra^III; Pedro Guarise da Silva^III

^IFull Professor, Department of Surgical Practice, Discipline of Coloproctology, Center of Health Sciences at the Universidade de Caxias do Sul (UCS) - Caxias do Sul (RS), Brazil

^IIResident physician, Service of General Surgery at the Hospital Geral, UCS - Caxias do Sul (RS), Brazil

^IIIAcademician, Medical Sciences at the UCS - Caxias do Sul (RS), Brazil

^{Correspondence to}

ABSTRACT

Granular cell tumor rarely affects the gastrointestinal tract. The symptoms are often unspecific and the diagnosis is reached accidentally by colonoscopy. We report the case of a 42-year-old patient diagnosed with granular cell carcinoma of the colon based on an incidental finding in colonoscopy, who was treated successfully by endoscopic excision of the tumor.

Keywords: colon; colonoscopy; granular cell tumor; endoscopy.

RESUMO

O tumor de células granulares raramente acomete o trato gastrointestinal. Os sintomas muitas vezes são inespecíficos e o diagnóstico é feito ao acaso através da colonoscopia. Nós reportamos o caso de um paciente de 42 anos diagnosticado com tumor de células granulares de cólon devido a um achado incidental da colonoscopia e tratado com sucesso com remoção endoscópica.

Palavras-chave: colo; colonoscopia; tumor de células granulares; endoscopia.

INTRODUCTION

Granular cell tumor, also known as granular cell myoblastoma¹, is a rare soft tissue tumor that affects any anatomical site, more commonly the oral cavity and tongue (33%), subcutaneous tissues (10%) and the musculoskeletal system (5%)^2,3. In the gastrointestinal tract, it affects most commonly the esophagus, followed by the stomach and duodenum². Its histogenesis is uncertain³; however, it is known to be a benign tumor that appears as a submucosal nodule, and which may be accidentally found during the endoscopic exam⁴.

We report the case of a patient with granular cell tumor, diagnosed and treated by endoscopy, with good progress after 24-month follow-up.

CASE REPORT

A 42-year-old man came to the outpatient clinic complaining of rectal prolapse, bleeding and pain at evacuation. At the physical examination, mixed hemorrhoids were observed, with no additional findings. In the preoperative period, laboratorial exams were performed and the patient was submitted to colonoscopy.

This examination showed the presence of three submucosal lesions in the cecum and ascending colon, which were resected after infiltration of the submucosa with saline solution, with no complication during the procedure. Macroscopically, the lesions presented around 5 mm diameter, were hardened and whitish. The material was sent for histopathological analysis, which showed lesions compatible with granular cell tumor, presenting dystrophic calcifications (Figure 1). The lesions were removed by endoscopic excision, with observational management. After 24-month follow-up, the patient remains asymptomatic and with normal colonoscopy.

DISCUSSION

Granular cell tumor rarely affects the gastrointestinal tract. The cellular origin of this entity is uncertain. In the beginning, it was believed to have a myoblastic origin, and for this reason, it was named granular cell myoblastoma. However, as it is positive to S-100 protein, it is thought to be a tumor of neural origin, more precisely, of Schwann cells⁵. The incidence of this neoplasm has not been defined, but it is supposed to affect more often men in his 40s or 50s².

When affecting the gastrointestinal tract, this tumor is usually located in the submucosa, covered by normal mucosa⁶. The tumor diameter varies from 1 to 2 cm, but tumors of 4 cm diameter have been reported, and it may be a single tumor or multiple tumors.

The tumor symptoms are unspecific. In most cases, the lesions are asymptomatic; and they may simulate other pathologies that affect the colon, such as hematochezia and abdominal discomfort^1,7. At colonoscopy, the aspect is similar to that of a sessile polyp, preferably located in the anorectal area and the ascending colon⁴. The endoscopic biopsy is not the best option, as in most cases, the tumor is covered by normal mucosa. The endoscopic ultrasound may suggest the diagnosis, but it does not always allow it to be distinguished from malign neoplasms⁸. The best diagnostic option is the mass surgical excision and histopathological analysis⁷.

Diagnosis is rarely difficult at the histopathological analysis, as the presence of nests of large cells with abundant cytoplasm and small and round nucleus is typical. The immunohistochemical analysis confirms the diagnosis when demonstrating positivity to S-100 protein, neuron specific enolasis and vimentin, and negativity to alpha smooth muscle actin and desmin¹.

As this is a benign pathology, the recommended treatment is the endoscopic excision of the lesion by extensive biopsy when the tumor diameter is smaller than 2 cm and not adherent to the muscularis propria, preventing complications such as perforation and bleeding⁶. In cases of multiple tumors, total colostomy is recommended. For single location of the tumor, but with diameter above 4 cm, colectomy is suggested, as tumors of this size present higher risk of malignity and metastasis⁴.

CONCLUSION

This report described a case of granular cell tumors in the ascending colon and cecum. The patient presented unspecific symptoms, which is typical of this pathology, and the disease was accidentally diagnosed during colonoscopy. The endoscopic excision is the recommended treatment and was successfully performed in the patient, with good clinical progress after 24-month follow-up.

Submitted on: 05/17/2011

Approved on: 05/30/2011

Financial source: none.

Conflict of interest: nothing to declare.

Study carried out at the Service of Coloproctology, Hospital Geral de Caxias do Sul - Caxias do Sul (RS), Brazil.

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Publication Dates

• Publication in this collection
  30 Aug 2012
• Date of issue
  June 2012

History

• Received
  17 May 2011
• Accepted
  30 May 2011