New radiological clues in the diagnosis of spindle cell oncocytoma of the adenohypophysis

Abstract

Aim: To present three new cases of spindle cell oncocytoma (SCO) from a single centre and to identify new radiological clues in the diagnosis of SCO according to the information obtained from the cases presented.

Materials and methods: Three adults with SCO confirmed at histopathology were retrospectively reviewed. The medical records, imaging findings, operative notes, and histopathology findings for each patient were recorded. Magnetic resonance imaging (MRI) findings were evaluated, including tumour localisation, tumour size, signal intensity, imaging features on T1-weighted and T2-weighted images, and contrast enhancement characteristics. The study protocol was approved by the institutional review board. Informed consent was obtained from each patient.

Results: T1-weighted imaging (WI) and T2WI demonstrated millimetric hypointense foci and linear signal void areas in all lesions. Consistent with the hypervascular features of the tumour, intense contrast enhancement was observed during the early stages of dynamic contrast enhanced (DCE) MRI. Linear signal void areas showed contrast enhancement, but some of the hypointense millimetric foci remained without contrast enhancement.

Conclusions: Although the radiological findings and preoperative diagnosis of SCO have been reported to be non-specific and impossible, respectively, in the literature, the characteristics of MRI and different patterns of contrast enhancement can help in recognising this rare entity. This article represents a single institution case series of SCOs and also includes the first description of a correlation of the histopathological findings with radiological findings and new clues in the differential diagnosis of SCOs. We described these new radiological clues as "Hasiloglu's Signs".