The interrelationship between tubular and papillary sectors of tubulo-villous colorectal adenomas: comparative morphometric analysis and evaluation of cell proliferation

In a series of 100 colorectal adenomas, 23 tubulo-villous adenomas were individualized through the identification of papillae as structures persisting for more than 100 microm in serial sections with a connective axis lined with epithelial cells. In these adenomas, the tubular and villous areas with the highest dysplasia were selected, and a morphometric analysis was undertaken to assess the Index of Structural Atypia, the Nucleo-Glandular Index, and the Nuclear Stratification Index. The AgNor count and the proliferating cell nuclear antigen (PCNA) Label Index (LI) also were performed. The overall mean of each of these indexes was significantly higher in the villous sector than in the tubular one (P < .001). In 16 cases, the semi-objective method of dysplasia gradation showed a superior degree in the papillary sector, whereas it showed an equal degree in the remaining seven lesions. The AgNOR count was significantly different in all cases, with higher values in villous sectors (P < .05). With the exception of one case, this was confirmed by the PCNA LI. The Stratification Index showed significantly different values in 20 cases, whereas the other morphometric indexes showed a less discriminatory result. Our findings objectively show that the degree of dysplasia in tubulo-villous adenomas should be analyzed in the villous sector. The existence of heterogeneous cellular populations has been confirmed both in the structural organization of cells and in some basic parameters such as the cell proliferation rate in colorectal adenomas. Our findings suggest that the occurrence of villous architectural growth is a secondary event in a tubular adenoma. Enhanced cellular proliferation of the villous area allows the progressive substitution of tubular structures.

Capsular pseudoinvasion after fine-needle aspiration of follicular adenomas of the thyroid

Two cases of an unusual finding of capsular pseudoinvasion in follicular thyroid adenomas after fine-needle aspiration (FNA) procedures are reported. These capsular breaches were noted along the hemorrhagic needle track, which traversed the normal peripheral thyroid parenchyma into the lesions. A reparative reaction was seen at some points along one of the tracks. Histologic examination also showed extrusion of the tumor parenchyma through the capsular interruption in one case. Surgical pathologists should be aware of this rare complication of FNA of thyroid follicular adenomas as a differential diagnosis of minimally invasive (encapsulated) follicular carcinoma.

[Primary small cell carcinoma of the esophagus]

Primary small cell carcinoma of the esophagus, morologically indistinguishable from its counterpart of the lung is a rare tumour with a frequency between 0.05 to 7.6% of all esophageal malignancies. Currently they are divided into oat cell and non oat cell, regarding the presence of neuroendocrine granules. We report 3 cases from our hospital. They were studied clinicopathologically and also examined by electron microscopy.

[Endoscopic-pathologic correlation of rectocolonic lesions less than 10 mm]

Ninety eight rectocolonic lesions up to 10 mm in diameter found in 50 patients were analyzed. The relationship between endoscopic and pathologic diagnosis was established. Emphasis was made on the detection of adenomas based in the following: Yamada III or IV lateral vision, Yamada I and II with smooth but erythematous surface, and in pale with irregular surface lesions. The sensitivity of the method was 92% and the specificity was 72% for adenomas. Six percent of adenomas were pale, with mucous hypersecretion on histopathology, and can be mistaken for hyperplastic polyps. This mucous hypersecretion correlates with low grade dysplasia, which supposedly indicates a lower evolutive risk.