No abstract

Background:In order to elucidate the significance of myofibroblasts in invasive growth of colorectal adenocarcinomas, we examined the number of myofibroblasts at the tumor border of colorectal adenocarcinomas.Method: A total of 91 invasive colorectal adenocarcinomas were examined immunohistochemically using anti-alpha-smooth muscle actin (ASMA) and high-molecular-weight caldesmon (h-CD) antibodies; 25 carcinomas confined to the submucosa (sm carcinomas), 40 carcinomas confined to the muscularis propria (mp carcinomas) and 26 carcinomas invading the subserosa or adventitia (ss carcinomas). We considered ASMA-positive and h-CD-negative stromal cells as myofibroblasts.Results: Twenty-seven (67%) of the 40 mp carcinomas and 25 (96%) of the 26 ss carcinomas had a small number of myofibroblasts at the tumor border facing the muscularis propria. Conclusions:Although direct evidence is lacking, there is a possibility that the further immediately vertical and radial invasion of carcinoma cells into the subserosa or adventitia is associated with a smaller number of myofibroblasts at the tumor border facing the muscularis propria in mp carcinomas, resulting in a low incidence of mp and a high incidence of ss carcinomas in the colorectum.

Gastric inverted hyperplastic polyp (IHP) is a rare type of gastric polyp, and is characterized by downward growth of the hyperplastic mucosal components into the submucosa. To the best ofour knowledge, 16 gastric IHP cases have been described in the English literature, but the pathogenesis has not been established. We report the clinical and pathological findings of four gastric IHP cases. The lesions were mainly composed of hyperplastic foveolar-type glands with focal cystic dilatation. Pyloric type glands, endocrine cells, acinic cell metaplasia, and smooth muscle bundles were also seen as components of the polyp. Two cases (cases 1 and 4) coexisted with multifocal gastritis cystica profunda (GCP) and gastric adenocarcinoma. Case 4 furthermore exhibited an intermediate form between IHP and GCP. We suggest that IHP may be GCP associated with exaggeratedly hyperplastic and metaplastic changes. In case 4, the coexisting gastric carcinoma was mainly located in the submucosa, whilst the mucosal component was minimal. Five out of twenty reported gastric IHP cases, including our cases, coexisted with gastric adenocarcinoma. These facts would lead us to further investigate the relation between gastric IHP and carcinoma.

Signet-ring cell carcinoma (SRCC) of the prostate is a very rare neoplasm and there have been only 38 cases reported to date. Here the 39th case of prostatic SRCC containing a small amount of neutral mucin, prostatic specific antigen (PSA) and prostatic specific acid phosphatase (PSAP) in the signet-ring cells is reported. It was also found that some intracytoplasmic lumina were derived from the shallow or deep invagination of luminal membranes of cancer cells that formed the neoplastic glands. Using immunohistochemistry, a combination of monoclonal antibodies against cytokeratins 7 and 20 as well as PSA and PSAP may be useful in differentiating prostatic primary SRCC from metastatic SRCC originating in the gastrointestinal tract.

These results suggest that CD34 expression in stromal cells is associated with progression of D-type GCs, and that absence of expression is also seen in I-type GCs that are progressing.