Colonic submucosal tumors: a new classification based on radiologic characteristics

Despite advances in gastrointestinal radiologic techniques, findings from barium enema studies cannot be used reliably to predict the histologic nature of a colonic submucosal tumor. Therefore, we generated a new and comprehensive classification system for all colonic submucosal tumors based on a correlation between their radiologic characteristics and their histopathologic features.

Between 1978 and 1990, 89 patients had 95 colonic submucosal tumors diagnosed on the basis of barium enema studies and confirmed by biopsy or surgery. Of these, 39 patients (44%) were symptomatic and 50 patients (56%) were asymptomatic. Single lesions (82 cases) and multiple lesions (12 cases of lymphoma and one case of blue rubber bleb nevus) were observed. The 95 lesions included 21 carcinoids, 27 malignant lymphomas, 17 lipomas, 10 lymphangiomas, six leiomyosarcomas, five leiomyomas, and nine others. We analyzed the radiologic findings and classified these lesions according to their appearance.

All tumors were classified on the basis of their morphologic appearance into five types: (1) wide-based sessile lesion with gradually sloping margin and smooth surface (17 cases); (2) wide-based sessile lesion, more polypoid than the first type, with a smooth surface, with or without a central depression (49 cases); (3) wide-based sessile lesion with lobulated surface (six cases); (4) pedunculated lesion with smooth or granular surface (17 cases); (5) unclassified, not any of the previously mentioned types, may be diffusely stenotic or aneurysmal (six cases). The most common finding was the wide-based sessile lesion with a smooth surface and a possible central depression; next most common was the wide-based sessile lesion with gradually sloping margin and smooth surface; next was the pedunculated lesion with a smooth or granular surface. Eighty-six percent of the lesions were single; 14% were multiple. Histologic confirmation revealed mainly lymphoma (29%) and carcinoid (22%), of which the most common finding was a wide-based sessile lesion with a smooth surface, with or without a central depression.

This new classification based on radiologic characteristics covers all varieties of colonic submucosal tumors. It can serve as a guideline for predicting a specific diagnosis of a colonic submucosal tumor on the basis of radiologic findings.