Clinicopathological Analysis of Densely and Sparsely Granulated Somatotroph Tumors of Pituitary

Abstract

ObjectiveSomatotroph tumors are the second most common type of pituitary neuroendocrine tumors (PitNETs) that can be further classified into two subtypes, namely densely granulated somatotroph tumors (DGSTs) and sparsely granulated somatotroph tumors (SGSTs). The aim of this study is to investigate the clinical significance of the two subtypes by conducting a retrospective analysis. MethodsFrom the database of the Ningbo Clinical Pathology Diagnosis Center, we collected cases diagnosed with pituitary somatotroph tumors. We then compiled pertinent clinical and radiological data and proceeded with histopathological examination involving HE staining and immunohistochemical staining. Subsequent tumor analysis comparing the two subtypes used either the Chi-square test or Fisher's exact test. ResultsIn this study, we analyzed a total of forty cases of somatotroph tumors, with 18 cases classified as DGSTs and 22 cases as SGSTs. The male-to-female ratio was 5:4 for DGSTs and 4:7 for SGSTs. The mean age was 52.83 years for DGSTs and 47.18 years for SGSTs. Statistically significant differences were observed between the DGSTs and SGSTs groups concerning invasiveness (P=0.0267) and postoperative remission (P=0.007). Both DGSTs and SGSTs cells exhibited co-expression of PIT1, GH, and CAM5.2, although the patterns of CAM5.2 expression differed between the two subtypes. ConclusionsThe efficacy of CAM5.2 staining in distinguishing between DGSTs and SGSTs was demonstrated. SGSTs, with their increased invasiveness and lower remission rate, emerge as a high-risk subtype. The histological subtype of somatotroph tumors plays a crucial role in guiding treatment decisions and prognostic evaluation in affected patients.