PMC6332978_01
(a) Contrast enhanced CT shows a 4.5 cm left upper pole renal mass. (b) Chest CT shows an ill-defined obstructive right perihilar mass, which is inseparable from the extensive mediastinal and hilar lymphadenopathy. There is irregular and nodular inter-/intra-lobular septal thickening predominantly in the right middle and lower lobe with ipsilateral pleural effusion, suggestive of lymphangitic carcinomatosis.
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fig1
A 67-year-old man with a significant smoking history presented with a 4.5 cm enhancing left upper pole renal mass detected on CT scan and treated by radical nephrectomy (Figure 1(a)). There was bilateral extensive mediastinal and hilar lymphadenopathy, and irregular inter-/intra-lobular septal thickening predominantly involving the right middle and lower lobe suggesting lymphangitic carcinomatosis (Figure 1(b)).
Photomicrographs of the primary kidney tumour. (a) There were two distinct morphologies. The main tumour showed a prominent papillary structure, eosinophilic cytoplasm, Fuhrman grade 3 nuclei (left). The smaller focus of tumour showed long tubular profiles or cord-like growth pattern of uniform, bland, low cuboidal cells with eosinophilic, focally vacuolated cytoplasm which transition to anastomosing spindle cells, with stroma showing myxoid and bubbly with abundant extracellular mucin (right). (b) The PRCC component showed positive staining for CD10 (left). The MTSCC component was negative for CD10 (right). (c) The PRCC component had small foci positive for synaptophysin. (d) Fluorescent in situ hybridization analysis showing three centromere 17 signals consistent with trisomy 17 in the PRCC component (left, green dots), while the MTSCC component was negative for trisomy 17 (right, green dots).
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Type 2 PRCC with a prominent papillary architecture. The cells were polygonal in shape and exhibited abundant eosinophilic granular cytoplasm and Fuhrman grade 3 nuclei (Figure 2(a), left). IHC showed positive staining for CK7, Racemase, and CD10 (Figure 2(b)). Additional IHC performed in retrospect, showing that a small focus of PRCC component was strongly positive for synaptophysin (Figure 2(c)) but negative for CD56 and chromogranin, indicating a neuroendocrine differentiation. A minor component (5%) of the tumor showed features of MTSCC (Figure 2(a), right). The nuclei in the PRCC component had three centromere 17 signals consistent with trisomy 17, those in the MTSCC component were negative for trisomy 17 (Figure 2(d)).
Photomicrographs of the lung metastasis. (a) A very infiltrative tumour in the submucosa of the bronchus with a nested and trabecular architecture and no definite papillary architecture. (b) The tumour was diffusely positive for synaptophysin. (c) The tumour was strongly positive for PAX8. (d) The tumour showed positive staining for CD10.
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The cells had a moderate amount of vacuolated, granular eosinophilic cytoplasm (Figure 3(a)) suggestive of an endocrine neoplasm. However, IHC showed an endocrine profile, diffusely positive for synaptophysin (Figure 3(b)) and focally for chromogranin and CD56.