Maureen F. Zakowski

Solitary fibrous tumor : A cytologic-histologic study with clinical, radiologic, and immunohistochemical correlations

Solitary fibrous tumors (SFT) are rare neoplasms that most commonly involve the pleura, mediastinum, and lung. They are believed to be submesothelial in origin. Histologically, they are characterized by fibroblast‐like cells and connective tissue in varying proportions. The “patternless pattern” and the hemangiopericytoma‐like pattern are the most common arrangements. The majority of SFTs have been immunoreactive for CD34. Very little has been reported regarding the cytologic findings in these tumors.

Use of thyroid transcription factor 1, PE‐10, and cytokeratins 7 and 20 in discriminating between primary lung carcinomas and metastatic lesions in fine‐needle aspiration biopsy specimens

The distinction of a primary lung carcinoma from a metastatic lesion is important, because the treatment and prognosis differ for patients with these malignancies. Such a distinction can be difficult because of overlapping cytologic features. It has been shown that antibodies to thyroid transcription factor 1 (TTF‐1) and PE‐10 are fairly specific markers for primary lung tumors in histologic specimens. TTF‐1 regulates the expression of surfactant protein production, and PE‐10 is a monoclonal antibody against components of human surfactant proteins. The combination of cytokeratin 7 (CK7) and cytokeratin 20 (CK20) immunoprofiling has been helpful in the identification of the primary site of origin of lung tumors.

The use of CDKN2A deletion as a diagnostic marker for malignant mesothelioma in body cavity effusions

The distinction between benign reactive mesothelial cells and malignant mesothelial cells in serous effusions is difficult and has an unusually high false negative rate. Unfortunately, there are no generally accepted markers to distinguish between benign reactive and malignant mesothelial cells. Homozygous deletion of CDKN2A is frequent in mesothelioma (present in > 70% of tumors). Therefore, detection of CDKN2A deletion by fluorescence in situ hybridization (FISH) was evaluated as an ancillary test in the cytologic diagnosis of malignant mesothelioma.

Diagnostic dilemmas in pulmonary cytology

Diagnostic difficulties in pulmonary cytology may be compounded by other medical problems, lack of pertinent information, and the presence of rare tumors. In the current study, the authors describe six cases of lower respiratory tract cytology that presented particular diagnostic challenges or pitfalls.

Cytopathology of insular carcinoma of the thyroid

Insular carcinoma of the thyroid (ICT) first was reported in 1984. To the authors knowledge, few cytology reports have been published since that time. The authors describe the cytologic features of six tissue‐proven ICTs and propose criteria that suggest its diagnosis.

The cytology of extraskeletal Ewing sarcoma.

Extraskeletal Ewing sarcoma (EES) shares histologic, immunohistochemical, and molecular findings with ES of bone. The authors goal in conducting this study was to examine the cytomorphologic features of EES. In addition, immunocytostaining for CD99/O13 was performed in all cases, and cytogenetic and molecular data were available in about half of the cases.

A spectrum of cytomorphologic variations in medullary thyroid carcinoma. Fine-needle aspiration findings in 19 cases.

Medullary thyroid carcinoma (MTC), a rare malignancy with a variety of morphologic appearances, can mimic both primary and metastatic lesions of the thyroid gland and give rise to diagnostic problems when these tumors are aspirated. Although cytopathologic features of MTC have been well described, this study was undertaken to define and elaborate further, subtle morphologic variations, the recognition of which would be helpful in the diagnosis of MTC.

Anti‐α‐inhibin

Anti‐α‐inhibin, an antibody directed against a peptide hormone, has been shown to be a useful diagnostic aid in surgical pathology material for the identification of sex cord–stromal neoplasms and recently has been described in adrenocortical carcinoma (ACC). The diagnosis of ACC versus renal cell carcinoma (RCC) may be difficult morphologically, particularly in fine‐needle aspiration (FNA) material. To date, the immunohistochemical distinction of ACC from RCC is based on a panel of antibodies that include vimentin, cytokeratins, and epithelial membrane antigen. However, the reliability of this panel is weakened by inconsistent staining patterns.

Cytologic features of sarcomas in fluids

Sarcomas account for < 6% of malignant effusions and their diagnosis usually is made in the setting of a known primary tumor. However, these tumors often exhibit a variety of features that can differ from those of the original neoplasm and may preclude the correct diagnosis. This article evaluates the cytomorphology of sarcomas in fluids and determines characteristic features for identification and classification.

Cytology of thymomas

Aspirates of thymomas are distinguishable from other lesions and fine‐needle aspiration (FNA) is a proven method for investigating mediastinal masses.