Prediction of aggressiveness of gastrointestinal stromal tumours based on immunostaining with bcl-2, Ki-67 and p53

OBJECTIVE: While the use of fine needle aspiration (FNA) in the diagnosis of gastrointestinal stromal tumours (GISTs) is well-established, it can be difficult to predict the prognosis of GIST based on morphology alone. The objective of the current study was to determine if expression of bcl-2, Ki-67 and p53 correlated with the outcome of GISTs based on cytological material. METHODS: Cell-blocks from 14 GISTs diagnosed by FNA were retrieved. Immunostaining was performed with antibodies against bcl-2, Ki-67 and p53. All cytological diagnoses were confirmed by positive immunostaining with c-kit and/or subsequent histological evaluation. Positivity for bcl-2, Ki-67 and p53 was defined as the presence of > or =10% cytoplasmic staining, > or =5% nuclear staining and > or =5% nuclear staining respectively. RESULTS: The 14 patients consisted of seven males and seven females with a mean age of 58 years. The average follow-up interval was 46 months. Six had a benign course and eight developed recurrences/metastases. Thirteen (93%) cases showed positive staining for bcl-2. Positive Ki-67 and p53 staining was noted in one (7%) and seven (50%) cases respectively. The difference in staining for p53 between aggressive and non-aggressive GISTs was statistically significant. No statistically significant difference was noted for bcl-2 staining or Ki-67 labelling index between the two groups. CONCLUSIONS: According to our observations, p53 immunostaining may be useful in predicting the outcome of GIST diagnosed by FNA; Ki-67 and bcl-2 are not useful as prognostic markers for GIST in FNA specimens.     

Diagnostic dilemmas of hyalinizing trabecular tumours on fine needle aspiration cytology: a study of seven cases with BRAF mutation analysis

T. Kim, Y. L. Oh, K. M. Kim and J. H. Shin Diagnostic dilemmas of hyalinizing trabecular tumours on fine needle aspiration cytology: a study of seven cases with BRAF mutation analysis Objective: Hyalinizing trabecular tumours (HTTs) are rare follicular‐derived neoplasms that behave in an almost benign manner. HTT is frequently misdiagnosed as papillary carcinoma by fine needle aspiration (FNA) cytology or as papillary or medullary carcinoma on surgical resection. Methods: The authors examined FNA material from seven cases of histologically verified HTT. Cytological findings were reviewed and correlated with ultrasonographic and histological features. In addition, MIB‐1 and calcitonin immunostaining was performed on surgical specimens, and BRAF mutation analysis on three pre‐operative FNA specimens and seven histology specimens. Results: The original cytological diagnosis was either suspicious or positive for papillary carcinoma in all patients. The FNA‐based differential diagnoses included HTT, papillary carcinoma or, less likely, medullary carcinoma in two patients. Aspirates showed oval to spindle‐shaped cells with frequent intranuclear inclusions, isolated in loosely cohesive groups with a trabecular or syncytial pattern in a bloody background. Radiating arrangements of tumour cells surrounding hyaline stroma with serrated calcifications and a lack of papillary or sheet‐like fragments may suggest HTT on FNA. Spherical calcified bodies and possible psammoma bodies were frequently found in three cases. Retrospectively, six of the seven cases showed membranous immunoreactivity for MIB‐1, but none of the seven possessed the BRAF (V600E) mutation or showed calcitonin reactivity. Conclusions: Although the recognition of HTT on FNA cytology is difficult, because of its morphological similarities to papillary and medullary carcinoma, its characteristic cytological features along with ultrasonographic findings may suggest the diagnosis preoperatively and avoid surgical over‐treatment.