Suitability of the Cellient^TM cell block method for diagnosing soft tissue and bone tumors

Abstract

BACKGROUNDThe diagnosis of tumors of soft tissue and bone (STB) heavily relies on histological biopsies, whereas cytology is not widely used. CellientTM cell blocks often contain small tissue fragments. In addition to Hematoxylin and Eosin (H&E) interpretation of histological features, immunohistochemistry (IHC) can be applied after optimization of protocols. The objective of this retrospective study was to see whether this cytological technique allowed us to make a precise diagnosis of STB tumors.METHODSOur study cohort consisted of 20 consecutive STB tumors, 9 fine‐needle aspiration (FNAC) samples, and 11 endoscopic ultrasonography (EUS) FNACs and included 8 primary tumors and 12 recurrences or metastases of known STB tumors.RESULTSIn all 20 cases, H&E stained sections revealed that diagnostically relevant histological and cytological features could be examined properly. In the group of 8 primary tumors, IHC performed on CellientTM material provided clinically important information in all cases. For instance, gastrointestinal stromal tumor (GIST) was positive for CD117 and DOG‐1 and a PEComa showed positive IHC for actin, desmin, and HMB‐45. In the group of 12 secondary tumors, SATB2 was visualized in metastatic osteosarcoma, whereas expression of S‐100 was present in 2 secondary chondrosarcomas. Metastatic chordoma could be confirmed by brachyury expression. Two metastatic alveolar rhabdomyosarcomas were myf4 positive, a metastasis of a gynecologic leiomyosarcoma was positive for actin and estrogen receptor (ER) and a recurrent dermatofibrosarcoma protuberans expressed CD34.CONCLUSIONIn the proper clinical context, including clinical presentation with imaging studies, the CellientTM cell block technique has great potential for the diagnosis of STB tumors.

Comparison of effusion cell block and biopsy immunohistochemistry in mesothelial hyperplasia, mesothelioma, and carcinoma in dogs

“…This could be accomplished by IHC on effusions prepared as cell blocks, which has been well established in human pathology for this purpose, including distinguishing adenocarcinoma, reactive mesothelial cells, mesothelioma, and carcinomas. 13,[15][16][17][18] In veterinary pathology, cell block IHC is a relatively new technique but has been used for distinguishing carcinoma, mesothelial cells, and lymphoma in cavitary effusions in dogs and cats. 19,20 However, our recently described IHC panel to aid in distinguishing benign from malignant mesothelial proliferations in biopsies from dogs 14 has not been applied to cell blocks.…”