September 2014 - Dr. Previn Gulavita
Clinical history: 63 year old male with left kidney mass.
Collecting Duct Carcinoma
This neoplasm arises in the principal cells of the collecting ducts of bellini. It is among the least common types of renal cell carcinoma, accounting for less than 1% of renal malignancies.
This neoplasm occurs more commonly in males (2:1 M:F ratio). A strong family history of various types of cancer in other family members has bee noted in some reports. The majority of patients present with abdominal pain or flank pain and hematuria. Imaging studies usually disclose the presence of a predominantly solid mass consistent with renal carcinoma.
Small collecting duct carcinomas are usually located centrally, and may be localized to a medullary pyramid. However, because collecting ducts extend from the medulla to the cortex, collecting duct carcinoma can originate anywhere in the parenchyma, and identification of the site of origin may not be possible, particularly in large tumours. The cut surface is usually gray-white and firm and areas of necrosis may be evident. In contrast to other types of renal cell carcinoma, the borders of collecting duct carcinoma are indistinct. Tumour involvement of the adrenal gland, perirenal fat, renal sinus fat, renal pelvis, Gerota’s fascia, renal vein and/or regional lympho nodes is grossly evident in the majority of cases.
Microscopically, collecting duct carcinoma shows a complex tubulopapillary architecture which may coexist with solid cord-like areas. Tubules lined by clearly malignant cells are present, singly or arranged to form complex interanastomosing structures. Some tumours have microcysts with intracystic papillary proliferations of high-grade carcinoma. The borders are ill-defined, with extensive infiltration of adjacent parenchyma and often an acute and chronic inflammatory cell infiltrate at the interface between tumour and normal parenchyma. Pronounced stromal desmoplasia is a constant feature. The epithelium lining native ducts adjacent to or distant from the main tumour mass may show marked cytologic atypia or frank carcinoma in situ. Tumour cells are almost always of high nuclear grade, with nuclear pleomorphism and prominent nucleoli and varying amounts of eosinophilic cytoplasm.
The presence of mucin is often demonstrable by mucicarmine, Alcian blue, or periodic acid-Schiff (PAS) stains, within the tumour cell cytoplasm, at the luminal borders, or extracellularly. Tumour cells typically show positive IHC staining for peanuot lectin agglutinin, Ulex europaeus agglutinin-1 (UEA-1), low molecular weight keratins and pan cytokeratin. Positive staining for CK19 and CK903 is common. Immunostains for proximal tubular markers such as villin and CD10 are usually negative. DNA ploidy studies have shown aneuploidy in a high percentage of tumours.
Cytogenetic findings have been variable. Losses of heterozygosity in 1q, 6p, 8p, 13q and 21q have been reported, as well as loss of Y. Tumour stage is often advanced at the time of presentation, and not surprisingly the prognosis is generally poor. Nearly half of patients have nodeakl and/or distant metastases at time of initial diagnosis. Approximately 2/3 of patients die within 2 years.