Mucinous tubular and spindle cell carcinoma

 

This is a 55-year-old male with a 7.5 cm right renal mass.

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Grossly the specimen shows a solid, bright yellow to brown renal mass with hemorrhage and necrosis.

At low power, the tumor shows expansile growth pattern with a well-demarcated boundary.

 

 

At higher power, the tumor shows aggregates of elongated, interconnected tubules with slitlike lumina, solid compressed cords, and myxoid stroma.

The tubular cells are positive for cytokeratin cocktail.

 

ABPAS (Alcian blue PAS) stain demonstrates mucinous nature of myxoid stroma and highlights basement membrane of the tubules. The image on the right/lower shows adjacent normal kidney tissue.

 

Colloidal iron stain hights mucin accumulation in the myxoid stroma. The image on the right shows adjacent normal kidney tissue.

Mucinous tubular and spindle cell carcinoma has been mainly reported in females with an age range of 17 to 78 years. Despite of a spindle cell component, it is considered as a low-grade carcinoma with a very low chance of metastasis.The origin of the tumor is still debatable. The ultrastructural study reveals its close resemblance to the normal loop of Henle. Although its IHC profile is similar to papillary renal cell carcinoma ( Am J Surg Pathol. 2006 30:13-9), it lacks the gains of chromosomes 7 and 17 and losses of chromosome Y that are prevalent in papillary renal cell carcinoma (Modern Pathology 2006 19:488–493).  VHL gene deletion has not been detected.

Contributed by Dr. Michael Chaump and Dr. Shaolei Lu

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