Penile metastases are very uncommon. Prostate cancer as the most frequent malignoma of the male is the main primary lesion. Metastases in the penis only occur at an advanced state of the tumour and with a high dedifferentiation, e. g., ductal adenocarcinoma. Changes in the morphology of the prostate carcinoma are specially known for the occurrence of small-cell neuroendocrine and undifferentiated carcinomas. Often prior to the transformation an anti-androgen therapy has been undertaken. At this state of the disease, there is only the possibility of a palliative therapy with a poor prognosis. The increasing histological dedifferentiation of the tumour tissue can make it difficult or even impossible to identify the primary lesion.

Actinomycosis is a rare infection mainly of the head and neck region (cervicofacial actinomycosis). The cause of this infection is bacterial invasion of the host's mucosal barrier with consecutive infiltration of the surrounding tissues. The treatment of choice after diagnosis is a prolonged course of high-dose antibiotics. The presence of abdominal actinomycosis is at a maximum of 25%, whereas renal involvement appears only sporadically. Aggravating causes for early diagnosis are the appearance of abscesses, fistulae and a debilitating illness resembling carcinoma and leading to surgery as the treatment of choice. Renal actinomycosis is a diagnostic challenge because it is included in the differential diagnosis of renal masses with coexisting B-symptoms. The suspicion requires surgical treatment--nephrectomy. We report on a patient who was transferred to our department for nephrectomy because of radiologically diagnosed renal and perirenal abscesses. The histological result showed renal actinomycosis.