Incidental lymphoma in radical prostatectomy PLND specimens: a case series.

Abstract

Introduction & Objectives: Pelvic lymph node dissection specimens from radical prostatectomy, may on rare occasions reveal haematological disease. In this case series, we describe the natural history of three cases of incidentally diagnosed lymphoma from pelvic lymph node dissections specimens at time of radical prostatectomy. Method(s): Three cases of incidental lymphoma diagnoses in radical prostatectomy pelvic lymph node dissection specimens analysed at a large private pathology provider in Melbourne, Australia were included. Informed written consent was obtained from all three patients for publication of this work. Result(s): The 1st case was of a 66-year-old gent, with biopsy proven Gleason 4 (70%) + 3 = 7 acinar adenocarcinoma. MpMRI of the prostate did reveal a borderline obturator node, whilst PSMA-PET (F-18 DCFPyL) revealed an intensely avid primary (SUVmax 12.1), with no local or distant PSMA-avid lymphadenopathy. The lymph node dissection specimens revealed a lowgrade B-cell lymphoma with immunophenotyping consistent with marginal zone lymphoma. Postoperative FDG-PET only revealed a mildly avid obturator node. At 20 months postoperatively, the patient remained stable on haematological surveillance with no cytopaenia, constitutional symptoms, lymphadenopathy or splenomegaly. The 2nd case was of a 68-year-old gent, with biopsy proven Gleason 3 + 4 (25%) = 7 acinar adenocarcinoma. MpMRI revealed borderline external iliac nodes, whilst PSMA-PET (F-18 DCFPyL) demonstrated no PSMA avid nodal or distant disease - although the anatomical correlation CT confirmed borderline external iliac nodes. MDT consensus was for ePLND to facilitate histological sampling at time of prostatectomy. The PLND specimens revealed a small lymphocytic lymphoma, and further cytogenetic FISH testing revealed normal cytogenetics. 2.5 years postoperatively, the patient remained stable on haematological surveillance without cytopaenia, B symptoms, lymphadenopathy or splenomegaly. The 3rd case was of a 61-year-old with Gleason 4 (70%) + 3 = 7 acinar adenocarcinoma. An mpMRI revealed bilateral enlarged inguinal lymph nodes, whilst PSMA-PET showed mildly avid retroperitoneal nodes, felt to be reactive. PLND specimens revealed a classic follicular lymphoma. He was planned for chemotherapy for his follicular lymphoma however this was deferred at the time of report whilst pending recover from endovascular aortic aneurysm repair. Conclusion(s): Pelvic lymph node dissections specimens from radical prostatectomy, particularly when non-PSMA avid lymphadenopathy is present, may harbour non-urological conditions such as lymphoma. On occasion, nodes which ultimately yield lymphoma may be mildly PSMA-avid, but this may be dismissed as reactive. Multidisciplinary team review of imaging is recommended preoperatively in these instances, potentially with the early involvement of a haematologist if lymphadenopathy is of unclear cause.