1. a. The presence of cytoplasmic nuclear inclusions is one of the features of papillary carcinoma but has been seen in other conditions of the thyroid, including Hashimoto thyroiditis and medullary carcinoma. It also has been reported in other non-thyroid diseases including lung carcinoma, melanoma, hemangioendotheliomas, hepatocellular carcinoma, pleomorphic adenoma, and other lesions as well.

2. d. Fluorescence in situ hybridization does not detect the S-phase of the cell cycle. S-phase can be determined using flow cytometry.

3. c. A quantitative method of ploidy expression is the DNA index (DI), which is the ratio of the mean tumor cells at G0 /G1. The DNA content of normal diploid reference cells is 1. The greater the deviation of the DI from 1, the more “aneuploid” the tumor. Flow cytometry for DNA content does not detect chromosomal translocations. Translocations can be detected by FISH analysis or PCR for the chimeric gene or transcripts.

4. d. These are psammoma bodies which are laminated calcific concretions seen frequently in papillary carcinomas including that of thyroid, ovary, endometrium, and kidney. They are commonly seen in meningiomas and in benign mesothelial hyperplasia. They are not known to occur in melanoma. Osteopontin protein has been reported to be involved in formation of psammoma bodies. Nanobacteria, a new controversial class of organisms, have been suggested as a possible cause.

5. b. Adenocarcinoma generally shows fine chromatin and sometimes chromatin clearing. The other listed features are common in adenocarcinoma.

6. b. Pleural fluid eosinophilia is seen in pneumothorax, thoracentesis, pleural biopsy or surgery, introduction of blood in the pleural space (from infarction or trauma), and a few malignancies including Hodgkin disease. Pleural fluid eosinophilia is not a known feature of SLL/CLL.

7. d. Radiation can lead to numerous cellular changes including pleomorphism, nucleoli and hyperchromasia. Radiation is, however, associated with low nuclear- cytoplasmic ratio. This is one of the features that help differentiate it from dysplasia/neoplasia.

8. c. Systemic lupus erythematosus is associated with pleural fluid lymphocytosis. Empyema causes neutrophilia, while Loeffler syndrome, parasites, and pneumothorax cause eosinophilia.

9. c. Price anomaly is a congenital disorder in which there is sequestration of part of the lung. It does not usually communicate with the pleural cavity. The other conditions are known to shed bronchial cells in the pleura.

10. d. In pelvic washing the mesothelial cells nuclei and nucleoli are not particularly prominent as these sells are not shed in an effusion which generally induces reactive changes including prominent nuclei and formation of cell balls.

11. b. This is a true mesothelial lesion and does not generally express CD34. This type of mesothelioma has the worst prognosis of all other histologic types. It can be confused with metastatic non-small cell carcinoma. This lesion does not shed cells in fluid.

12. a. Mesothelioma association with SV40 beyond doubt has not been established in humans.

13. b. This is true mesothelioma. Vacuoles in mesothelioma are positive for oil red O (which stains fat) but not mucicarmine (which stains mucin). Currently, calretinin, thrombomodulin, WT1 gene product, and keratin 5/6 are considered the best antibodies for the identification of mesothelial differentiation. It is generally advised that, in addition to positive “markers,” immunostaining panels should also include antibodies which should be negative in mesothelial cells and which may be positive in adenocarcinoma, particularly carcinoembryonic antigen (CEA), Ber EP4, Leu M1, MOC31, or B72.3

14. d. This is a body-cavity based lymphoma. All the viruses listed, except SV40, have been implicated in the lesion.

15. c. Desmoplastic small round cell tumor of the pleura resembles that of intra-abdominal desmoplastic small round cell tumor and is positive for desmin and cytokeratin.

16. a. Both have small but visible about of cytoplasm. The other features favor anaplastic large cell lymphoma.

17. d. CD15 does not stain anaplastic large cell lymphoma.

18. c. Pseudomyxoma peritoneii is caused by MUC2 mucin producing tumors, usually from the appendix or ovary. Lobular carcinoma of the breast is not known to be associated with pseudomyxoma peritoneii.

19. b. High nuclear cytoplasm ratio is present in both conditions. The other features suggest small cell carcinoma.

20. c. CLL/SLL is negative for CD10. CD10 stains follicular lymphoma.

21. d. Cell block is not a routine method for CSF. The material is usually not sufficient to be processed for cell block.

22. a. To obtain a satisfactory specimen using FNA, small bore needle is better than large bore needle. Large bores (in excess of 23G) usually result in bleeding, which dilutes the specimen.

23. b. Kaposi sarcoma is not a contra-indication for FNA. Following FNA, carotid body tumor is known to be associated with thrombosis of carotid artery while pheochromocytoma may be followed by hypertensive crisis. Aspiration of an Echinococcus cyst (hydatid cyst) is known to be followed by anaphylaxis.

24. d. The best position for the thyroid FNA is to let the patient lie flat without the pillow.

25. a. FNA is helpful when the clinical suspicion is low. Core biopsy is the preferred methods in the other three conditions.

26. c. This is subareolar abscess. It affects both men and women and does no heal without excision.

27. a. This is fat necrosis. It affects elderly more than young women.

28. c. Smear of lobular carcinoma is usually associated with single cells. These are benign ductal cells and could be present in all of the other lesions.

29. d. This is a fragment of stroma with few cells in between the fibers. The stromal fragments in phyllodes tumor are characteristically cellular fragments.