Petris, Giovanni De

BACKGROUNDThe cytological diagnosis of malignant mesothelioma (MM) on serous effusion is challenging due to significant morphologic overlap with reactive mesothelial cells and adenocarcinoma. One of the morphologic features of MM in effusion cytology, small orangiophilic squamous‐like cells (SOSLC), has received little attention. To the best of the authors' knowledge, the current study is the first to assess the sensitivity and specificity of SOSLC in serous effusion specimens from histology‐proven MM cases along with those of reactive mesothelial and adenocarcinoma cases.METHODSA total of 130 cases of pleural (86 cases) and peritoneal (44 cases) effusion cytology cases (30 with histology‐proven MM, 41 with adenocarcinoma, and 59 with reactive mesothelial cells) were studied. The presence or absence of SOSLC was recorded in each case.RESULTSThe cytological diagnoses of the 30 histology‐proven MM cases included 1) atypical mesothelial cells, favor reactive (4 cases); 2) atypical mesothelial cells, suspicious for or cannot exclude mesothelioma (18 cases); and 3) positive for MM (8 cases). SOSLC were found in 10 of the 30 MM effusion cases (33.3%), 1 of the 41 adenocarcinoma cases (2.4%), and 5 of the 59 reactive mesothelial cell cases (8.5%). SOSLC were more likely to be present in MM effusions compared with either adenocarcinoma (P < .0001) or reactive mesothelial cell (P < .02) effusions. All 10 cases of MM with SOSLC were from pleural fluids. One case of peritoneal serous adenocarcinoma had SOSLC and 5 cases of reactive mesothelial cells in peritoneal fluid were found to have SOSLC.CONCLUSIONSAlthough not sensitive, the presence of SOSLC is quite specific for MM in pleural fluid cytology specimens. Finding this morphological feature in pleural fluid should alert the pathologist to a possible diagnosis of MM.Cancer (Cancer Cytopathol) 2014;122:70–75. © 2013 American Cancer Society.

A significant mimicker of malignancy in the esophagus is the presence of atypical/bizarre stromal cells (BSCs). Two patients, a 60-year-old woman and a 59-year-old man, with esophageal polyps at the gastroesophageal junction showed highly atypical/bizarre cells in the polyps’ stroma. BSCs were admixed with inflammatory cells and had large atypical nuclei, prominent nucleoli, and variably abundant amphophilic cytoplasm. Immunohistochemical studies showed that BSCs expressed vimentin whereas S-100, CD68, HMB45, CD45, Pan-cytokeratin, CK5/6, p63, CD10, EMA, MART-1, desmin, smooth muscle actin, CD31, CD34, and CMV were negative. Ki-67 showed low proliferative rate (less than 1% positivity). No evidence of intracellular mucin was found after histochemical stains (AB/PAS and mucicarmine). Follow-up endoscopic mucosal resection was available in both cases and showed benign esophageal mucosa and submucosa with disappearance, in one case, or marked decrease of BSCs. Esophageal BSCs reports in the literature invariably locate them in distal esophagus polyps or masses. Awareness of BSCs, of their location and associations, may help to prevent misdiagnosis of malignancy. The literature of esophageal BSCs is reviewed and the approach to this abnormality is discussed.

A 66-year-old male patient presented with nausea, abdominal pain, occasional rectal bleeding, progressive dysgeusia, onicodystrophy, and alopecia. Endoscopic exam and biopsies revealed severe atrophy and diffuse marked edema of mucosa of stomach and duodenum. No evidence of polyps was found in any portion of the gastrointestinal tract. The diagnosis of Cronkhite–Canada syndrome (CCS) was rendered. The patient symptoms resolved completely after initiation of steroid treatment. This additional case of CCS illustrates how the diagnosis of CCS does not require the presence of polyps but is defined by the appreciation of the diffuse marked edema and atrophy of the gastrointestinal mucosa.