Although rare, there are cases within reported series of men with GS≤6 in radical prostatectomies that have pelvic lymph node (LN) metastases. However, there are no studies as to whether pelvic LN metastases occur in tumors GS≤6 using the International Society of Urological Pathology (ISUP) updated Gleason scoring system. We performed a search of the radical prostatectomy databases at 4 large academic centers for cases of GS≤6. Only prostatectomies submitted and embedded in entirety with pelvic lymph node dissections were included. A combined total of 14,123 cases were identified out of which 22 cases had a positive LN. Histopathology review of 19 cases (3 cases unavailable for review) showed higher grade than originally reported by the pathologists in all cases. Of the 17 pre-ISUP reviewed cases, 2 were upgraded to 4+3=7 with both cribriform and poorly formed glands. One case was upgraded to 4+3=7 with tertiary pattern five displaying cribriform glands, poorly formed glands, and cords of single cells. Eleven cases were upgraded to 3+4=7 with glomeruloid structures and small to large cribriform glands (1 of these also had ductal adenocarcinoma features). Two cases had tertiary pattern 4 with small cribriform glands. One case had a prominent colloid component that would currently be graded as 4+5=9 due to large cribriform glands and solid sheets of cells within mucin. Of the two post-ISUP cases, one demonstrated tertiary pattern 4 and the other showed Gleason score 3+4=7 with irregular cribriform glands. Under-grading primarily accounts for LN positivity with GS ≤6, which has decreased significantly since the adoption of the ISUP grading system in 2005. Out of over 14,000 totally embedded RPs from multiple institutions, there was not a single case of a GS≤6 tumor with LN metastases. In contrast to prevailing assumptions, Gleason score ≤6 tumors do not appear to metastasize to lymph nodes. Rather, Gleason patterns 4 or 5, as better defined by the current ISUP updated grading system, is required for metastatic disease.

No abstract

Key morphologic clues and a focused immunohistochemical panel, including CK7, α-methylacyl coenzyme A racemase (AMACR), TFE3, cathepsin K, and carbonic anhydrase IX (CAIX), now allow most resected RCCs with papillary architecture and clear cells to be accurately classified. In other cases, cytogenetic and molecular findings can establish the diagnosis. Despite these tools, some RCCs with papillary architecture and clear cells do not fit into any of the described entities and currently remain unclassified.

Fibrolamellar carcinomas are a unique type of liver carcinoma that arise in non-cirrhotic livers of young individuals. Despite their distinctive appearance, recent studies have demonstrated a lack of consistency in how fibrolamellar carcinomas are diagnosed by pathologists. As a potential aide in diagnosis, we investigated the staining properties of CD68. The CD68 gene encodes for a transmembrane glycoprotein located within lysosomes and endosomes. Macrophages as well as other cell types rich in lysosomes/endosomes are CD68 positive. Cases of fibrolamellar carcinoma were collected from four academic centers. Control groups included hepatocellular carcinomas arising in both non-cirrhotic livers and cirrhotic livers. A group of cholangiocarcinomas were also stained. CD68 immunostaining was scored for both intensity and distribution on a scale of 0 to 3+. Twenty-three primary fibrolamellar carcinomas and 9 metastases (total of 24 individuals) were immunostained and showed a distinctive granular, dot-like or stippled pattern of cytoplasmic staining in nearly all cases (31/32), with a median distribution and intensity score of 3+. In control hepatocellular carcinomas that arose in non-cirrhotic livers, 10/39 showed CD68 staining with a median distribution and intensity score of 2+. In hepatocellular carcinomas arising in cirrhotic livers, 3/27 cases showed CD68 positivity, all with stippled dot-like cytoplasmic staining similar to that of fibrolamellar carcinomas. All 5 cholangiocarcinomas were negative. Overall, CD68 positivity was strongly associated with fibrolamellar carcinomas, p<0.001 and had a sensitivity of 96%, a specificity of 80% and a negative predictive value of 98%. In sum, tumor positivity for CD68 staining was highly sensitive for fibrolamellar carcinoma and a lack of CD68 staining should suggest caution in making a diagnosis of fibrolamellar carcinoma.