Radiology Quiz 19018 | Radiopaedia.org

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Findings

Intussusception is mostly seen in what demographic?

90% occur in children (although usually not infants).

What generalisation can be made about the presence or absence of a pathological lead point?

In children the vast majority do not have an identifiable lead-point, usually attributed to prominence of mucosal lymphoid tissue. In adults (and infants) the majority have a lead point, more frequently malignant in the large bowel, and benign in the small bowel.

The patient went on to have a laparotomy and the involved segment of bowel resected.

Histology

MACROSCOPIC DESCRIPTION:

Small bowel 470mm in length and 30mm in diameter. The serosal surface is mildly congested. On the mucosa, three firm, sessile polypoid lesions are identified. The first and third are pale tane. The second nodule has a pigmented brown-black appearance. The remainder of the mucosa is unremarkable.

MICROSCOPIC DESCRIPTION:

Sections of the small bowel show three nodules of malignant melanoma. The tumour forms fascicles of spindle cells as well as nests of more epithelioid cells. The tumour nodules are well-demarcated. The tumour extends from the mucosa to the subserosa. It is close to but not breaching the serosa. The tumour cells have elongated pleomorphic nuclei, conspicuous nucleoli and small amounts of ill-defined pale eosinophilic cytoplasm. Some of the tumour cells contain brown pigment in the cytoplasm. Scattered mitoses are seen. There is no evidence of lymphovascular invasion. 13 lymph nodes are identified with no evidence of metastatic melanoma. All the nodules are completely excised with clear proximal and distal resection margins. The tumour cells are S-100 and melan-A positive. DOG1 is negative.

FINAL DIAGNOSIS: Jejunal excision: Malignant melanoma x3.