Immunocytochemistry on scrape cellblock: An aid in the diagnosis of metastatic neoplasm with unknown primary: A series of four cases.

Scrape cellblock (SCB) is a novel technique to suggest possible primary site in fine-needle aspiration cytology (FNAC) smears from the liver, lung, and lymph nodes which are the common sites of metastasis of many primary tumors. Immunocytochemistry (ICC) on SCB averts the need of more invasive diagnostic procedures and gives a conclusive diagnosis. We present a series of four cases with unknown primary site, in which ICC was done on SCB to suggest possible primary site. Three of them were liver space-occupying lesions (SOL) and one from the periportal lymph node. In all four cases, wet-fixed smear for hematoxylin and eosin stain was prepared as routine procedure. FNAC was reported as metastatic adenocarcinoma in two and metastatic spindle cell neoplasm in one liver SOL. Periportal node was reported metastatic adenocarcinoma. Two hematoxylin and eosin-stained slides from each case with higher cellularity were used to scrape off the material to prepare SCB. ICC was put which gave conclusive diagnosis in all the cases. On ICC, two cases of metastatic carcinoma in the liver were diagnosed as metastatic neuroendocrine neoplasm from Gastrointestinal Tract and metastatic adenocarcinoma from the stomach. Spindle cell neoplasm of the liver was diagnosed as gastrointestinal stromal tumor from the stomach. Pancreatic head mass in metastatic periportal node was confirmed later by radiologic examination. SCB is a useful technique to make the best use of available material where reaspiration is difficult. ICC on SCB is of maximum utility to suggest possible primary sites in metastatic cases with unknown primary or where biopsy of the lesion is not possible.