GASTROINTESTINAL SCHWANNOMA: CASE REPORT

Schwannoma is a benign, neurogenic, slow-growing neoplasia, originated from Schwann cells, which are responsible by the myeline sheath on the peripheral nerves. This type of tumor is found more frequently on the central and peripheral nervous system and rarely occurs on the gastrointestinal tract1,2,4,5,6,8,10. Along with leiomyoma, leiomyossarcoma, gastrointestinal stromal tumor (GIST) and others, it makes part of the mesenchymal gastrointestinal tumors group2,5,6,10.

The anatomopathologic analysis have highlighted a fusiform cell mesenchymal lesion, extending from colon submucosa until its subserous layer, with moderate cell nucleus atypia and two mitosis per 50 high-power fields, without evidence of hemorrhage or necrosis.
Immunohistochemical research showed positive results for kit gene products (C-kit/CD117) and for glial fibrillary acidic protein (GFAP) and S-100 protein. The results for hematopoietic cells antigene (CD34), desmine and smooth muscle actin (CD117) were negative. This profile was compatible with a gastrointestinal tract schwannoma diagnosis.
The initial evaluation is made by computed tomography or nuclear magnetic resonance (NMR) to determine location, size, density of the lesion and attempt to identify metastasis 2 . Colonoscopy usually shows unharmed mucosa and an insert image sugesting extrinsic compression of intestinal lumen. However, all mesenchymal tumors have similar colonoscopic image aspect, making it difficult to set an specific diagnosis. In addition, a colonoscopy guided biopsy is not always able to collect sufficient amount of tissue to ensure a correct diagnosis 5 . Thus, anatomopathological and immunohistochemical research of the surgically resected lesion is mandatory 4,5 .
Therefore, in case of dealing with a resectable neoplasia, with high probability of mesenchymal tumor, surgical approach is indicated, with wide margin lesion resection, without necessity of lymphadenectomy, since the risk of metastasis in those cases is very low 1,2,4,5,6,9,10 . Considering the higher prevalence of GIST, the majority of schwannomas is misdiagnosed, until histological and immunohistochemical research and differentiation is concluded 4,5 . Schwannoma presents significant cell pleomorphism, lymphoid follicles, rare mitotic cells and rare necrotic spots. GIST shows high mitotic index, necrotic and hemorragic spots, without lymphoid follicles. Leiomyoma, on the other hand, does not show any of those characteristics 2,3,6 . The most important immunohistochemical markers are CD117, CD34, S-100 protein, GFAP, SMA and desmine. Schwannoma is S-100-and GFAPpositive, but CD117-and SMA-negative. GIST is CD117-and CD34-positive, S-100-and GFAP-negative. Leiomyoma is CD117-, CD34-, S-100-e GFAP-negative. However, the latest is desmine-and SMA-positive, which are negative markers on schwannoma and GIST 4,5,6,7 (Figure 2).

INTRODUCTION
S uicide is among the top ten causes of death in all age groups and with higher incidence between 15 and 35 years. Its incidence is increasing in young population 7 .
According to the World Health Organization, various stress conditions can increase the risk of suicide 1 . Eighty-five percent of patients who ingest foreign body have previous psychiatric illness and 84% of these patients have had previous intakes 5 .
From ingested foreign bodies 90% pass spontaneously through the gastrointestinal tract; 10-20% requires endoscopic removal; and 1% surgical approach 6 . In the general population, the foreign bodies are more often accidentally ingested such as bones, thorns or fruit stones. Most are housed in the physiological constrictions of the esophagus or abnormal narrowing sites (stenosis, rings or malignant tumors).
Here is presented one case of self-extermination attempt with continuous intake of nails in the course of a year.

CASE REPORT
Teenager of 16 year old was admitted with nails intake history during one year claiming attempt to self-extermination after constant arguments with his father and continuous nails intake. The parents were scavengers and had woodwork in which the patient had free access to the ingested material. Two days of admission he had epigastric pain, vomiting, and an episode of blackened stools. Physical examination showed good general condition, no collaborative, pallid (1+ / 4+), emaciated, heart beat 105 bpm, blood pressure of 120x80 mmHg, flat and flaccid abdomen, painful to deep palpation of epigastrium and no sudden pain to decompression. A large number of nails in the left iliac fossa was seen in abdominal radiograph ( Figure  1); blood count was with leukocytosis and left shift.