Classically characterized by its papillary appearance, papillary thyroid carcinoma is the most common malignant neoplasm of the thyroid. Several variants of papillary carcinoma have been described considering size (microcarcinoma); nature of the tumor boundaries (encapsulated); architecture (follicular, macrofollicular, cribriform-morular, solid, micropapillary); cellular characteristics (tall cell, columnar, oncocytic, clear cell, hobnail); additional tumor components (papillary carcinoma with focal insular component, papillary carcinoma with spindle and giant cell carcinoma, papillary carcinoma with squamous cell carcinoma, papillary carcinoma with mucoepidermoid carcinoma); stromal features (papillary carcinoma with fasciitis like stroma); or a combination of the abovementioned characteristics (diffuse sclerosing, Warthin-like). Although most variants do not pose any diagnostic problems; some histological variants can be challenging to the pathologist and some are of clinical significance, because of prognostic implications or accompanying clinical conditions. It is not rare to find a papillary carcinoma showing characteristics of more than one variant. For example: an individual tumor can show hobnail features and present as a microcarcinoma; another case can show solid architecture and clear cytoplasm. In such cases, it is more important to comment on clinically relevant morphological characteristics of the tumor, rather than religiously trying to classify an individual tumor into a particular variant. In this review, pathologic and clinical features of papillary carcinoma variants are summarized.

No abstract

The role of calcium independent inducible nitric oxide synthase (iNOS) in breast carcinoma is controversial, and the implications of iNOS expression on prognosis are not known. In this study, we aimed to investigate the significance of immunohistochemical iNOS expression in 100 invasive ductal carcinomas. In addition, 11 normal breast tissues, 20 cases of usual ductal hyperplasias (UDHs) and 20 fibroadenomas were included. We found that 78% of malignant and 75% of benign cases showed iNOS immunoreactivity. However, the intensity and the quantity of iNOS expression were significantly higher in the cancer group when compared with benign breasts (P<0.001), suggesting a role of iNOS in breast carcinogenesis. We were unable to show a correlation between iNOS expression and tumor grade, axillary lymph node status, and estrogen receptor expression. In 50 axilla negative cases having 5--12 years follow-up, disease free survival (DFS) rate was significantly lower in cases showing strong iNOS expression (P=0.05). As strong iNOS expression was correlated with short DFS, we concluded that further studies would be necessary to elucidate if iNOS expression might be a useful prognostic marker in breast carcinoma, especially in the axilla negative group.

We report a case of a 45-year old woman who was found to have a giant mediastinal tumour with radiological degenerative changes. She underwent thoracotomy to remove the mass, which was eventually diagnosed histologically as an ancient schwannoma, whereas cytological interpretation of the accompanying pleural fluid was malignant. Ancient schwannoma is a rare variant of schwannoma, histologically showing atypical features that may result in erroneous diagnosis of a malignant tumour. Clinical and radiological findings are important aids for further consideration of surgical removal of these potentially resectable tumours.

Primary liposarcomas of the mediastinum are unusual tumors. We report herein a case of a 52-year-old woman, who was found to have a mediastinal tumor involving both hemithoraces and radiologically showing non-resectable-invasive features to the adjacent vital structures. She had a history of left thoracotomy for mediastinal schwannoma 14 years previously. The patient underwent an exploratory thoracotomy following a preoperative misdiagnosis of an ancient schwannoma. Complete removal of the tumor was accomplished through a right posterolateral thoracotomy with a subsequent histological diagnosis of a recurrent low-grade liposarcoma. A resectable liposarcoma should be considered in the differential diagnosis of a mediastinal tumor, although radiologically, the tumor presents with invasive features.