Answer: Metastatic prostatic adenocarcinoma

Histology: The lymph node is replaced as variably sized nests of cells with a cribriform pattern. In some areas the cribriform pattern is well developed with round lumina and in other areas the cells have a more solid appearance with only a vague microacinar appearance. The nuclei are relatively uniform in size and shape and have prominent nucleoli. The cytoplasm is lightly eosinophilic. Mitotic figures are not readily identifiable.

Discussion: This is a classic case of prostate cancer presenting as a metastasis to the left supraclavicular lymph node with an occult prostate primary. Although it may seem incongruous for prostate cancer to present as a lymph node metastases within the neck, once one understands the anatomy, this finding is not so surprising. The thoracic duct drains from the abdomen and empties into the left neck. In addition to the prostate presenting with left neck metastases, other intra-abdominal tumors such as gastrointestinal, pancreatic, or ovarian may also present in a similar fashion. While typically the left side is involved initially, the right side may be involved after significant involvement of the left side. In a prior study, rectal examination was normal in approximately half of these patients. In this case, the morphology is typical of cribriform adenocarcinoma of the prostate. In addition to the cribriform architecture, the cytology is classic for prostate cancer where despite being present as a metastatic deposit the nuclei are relatively uniform with central nucleoli and lack of significant mitotic activity. The more subtle cribriform formation is also typical of prostate cancer. Although these areas lack the well developed round lumina seen in other areas of the tumor, this attempt at cribriform formation resulting in almost pseudorosette-like appearance is typical of Gleason score 5+5=10 prostate cancer and in many cases may be the clue to performing immunohistochemical stains to identify the lesion as being of prostatic origin. It is important to recognize metastatic adenocarcinoma of the prostate as some of these men may respond to hormonal therapy. Approximately one-third of the patients who presented with metastatic prostate cancer to supraclavicular lymph nodes have no evidence of bone metastases.

Reference(s):
– Am J Surg Pathol 11:457-63, 1987.