Primary Bowel Malignant Melanoma with Ileo-Ileal Intussusception

DOREL FIRESCU2, CRISTINA SERBAN2*, ANCA NEAGU1, DANIELA MIHALACHE1, LAURA REBEGEA3 1Dunarea de Jos University of Galati, Faculty of Medicine and Pharmacy, Morphological and Functional Sciences Department, 47 Domneasca Str., 800008, Galati, Romania 2Dunarea de Jos University of Galati, Faculty of Medicine and Pharmacy, Surgical Clinical Department, 47 Domneasca Str., 800008, Galati, Romania 3Department of Radiotherapy, Sf. Ap. Andrei Emergency Clinical Hospital, 177 Brailei Str., 800578, Galati, Romania


Experimental part Material and method
A 77 years old patient from urban environment is admitted to Surgery Clinic II, Sf. Ap. Andrei Emergency Clinical Hospital, Galati, for diffuse abdominal pains, melena, slow bowel movement for feces and gases, weight loss, marked physical asthenia, which had started insidiously 1 month ago. At the admission to hospital, the laboratory explorations had observed the following pathological modifications: WBC 14890/mmc, Hb 8.9 g/ dL, Ht 28.10 %, PLT 723000/mmc, urea 41 mg/dL.Plain abdominal radiography without changes;the abdominal ultrasound highlighted intestinal loop with reduced peristaltic. Superior and inferior digestive endoscopy did not find the existence of a tumor formation, the tumor markers being in normal limits. After a preliminary hematic rebalancing, it was decided to perform exploratory laparotomy, during which jejunal and ileal disseminated tumors, entero-enteral intussusception had been observed. Minimum segmental enterectomy, desintussusception was performed for biopsy. His evolution after surgery was favorable, the patient being released from hospital after 12 days from the surgery. The conventional histopathological exam in the standard coloration, hematoxylin-eosin (H&E), was performed in 6 blocks included in paraffin, which included fragments of small bowel, presenting at submucous level, with mucosa muscular compliance, focally with protrusion in the lamina propria, with mucosal ulceration, a malignant tumor proliferation with architecture under the form of compact strands and marginal nests composed of epithelioid cells with moderate and focally marked nuclear pleomorphism, frequent mitotic figures and frequent apoptosis, with moderate inflamed peritumoral lymphocytic infiltrate, with area-associated macrophages, some pigmented (melanophages). Intravascular-lymphocytic tumor emboli (LV1) was detected and perineural invasion (Pn0) was not detected.
The immunohistochemical complementary tests (IHC) revealed the following: melanocytic markers HMB45, Melan A, MITF, S100 had positive, diffuse reactions in tumor proliferation; the Ki67 proliferation index was positive in about 95% of the tumor cells, indicating intense mitotic activity, CK8 / 18 -absent reaction in tumor proliferation, positive in the intestinal epithelium excluding adenocarcinoma diagnosis, CD45 -absent reaction in tumor cells, positive in intra-and peritumoral lymphocytes, excluding lymphoma diagnosis, c-KIT -membrane reaction with low and moderate intensity in about 30% of Thus, histopathological diagnosis was established: multiple intestinal malignant melanoma determinations with epithelioid cellularity, with present lymphatic invasion (LV1) with HMB45 +, Melan A +, S100 +, MITF + immunophenotype.

Results and discussions
Normally, the small bowel and the colon do not contain melanocytes. Embryonically, they appear from the neuronal melanoblasts that migrate to distal ileum through the umbilical-mesenteric tract [7,8]. They differentiate by Amine Precursor Uptake and Decarboxylase (APUD), and may undergo neoplastic transformation in non-cutaneous situses [9]. According to this theory, the ileum is the most common situs for the development of primary melanoma of the small bowel, although some authors still deny the primary existence of melanoma in the gastrointestinal tract.
Some researchers believe that all melanomas of the GI tract would be metastatic in origin [2,10,11]. This opinion is based on the fact that some epidermal melanomas can regress spontaneously [9,12].
Before diagnosing malignant melanoma of the small bowel, it is important to exclude other primary melanomas in other situses. The criteria for the diagnosis of primary melanoma include: the absence of other melanomas in primary situses and without history of atypical melanocytic lesions at skin, retina, anal tract level and occasionally at penis, esophagus or vagina level [1,2].
In order to determine if malignant melanoma of the small bowel is a primary lesion, Sacks et al. [13] established three diagnostic criteria: i) single lesion, ii) other organs without primary lesions and absence of lymph ganglion enlargement, and iii) survival time over one year after diagnosis. [14]. In another study, Blecker and et al. [15] proposes the following criteria for the diagnosis of primary intestinal melanoma of the small bowel: i) the presence of a solitary mucosal lesion in the intestinal epithelium ii) the absence of melanoma or atypical skin melanocytic lesions and iii) the presence of intramuscular melanoma lesions in the upper or adjacent intestinal epithelium.
Histological criteria for highlighting the primar y melanoma are the proliferation of atypical junctional melanocytes and atypical melanocytic cells in the basal layer of the surface epithelium. Other indications of primary lesions are the presence of peritumoral lymphocyte infiltration [3,16].

Conclusions
Primary malignant melanomas of the small bowel are extremely rare neoplasms. They are solitar y, endoluminalmasses with aggressive clinical progression and poor prognosis. Surgical resection is essential to improve the prognostic.