Histologically, both ovaries consisted of a
clear cell tumour arranged in a solid, alveolar, microcystic and macrocystic pattern and showed a prominent vascular network (Fig.
8.: On the left, low power magnification of thrombus showing cast-like shape containing a
clear cell tumour. On the right, high power view shows large cells with cleared cytoplasm consistent with renal cell carcinoma.
The pathological differential diagnosis of MEC of the lacrimal gland may include inverted duct papillomas, cheilitis glandularis, necrotizing sialometaplasia, cystadenoma, cystadenocarcinoma, sebaceous carcinoma and other
clear cell tumours, adenosquamous carcinoma, metastatic squamous cell carcinoma, and rarely pleomorphic adenoma.
Our sub-analysis of the 544
clear cell tumours showed results similar to those of the larger cohort, with a tendency toward increased recurrence in patients who used metformin (HR, 1.7; 95% CI, 0.89-3.05[p = 0.09]), and no difference in CSS (HR, 0.9; 95% CI, 0.27-3.05 [p = 0.5]) (Fig.