BERKELEY, CA (UroToday.com) - While most carcinomas of the prostate are adenocarcinomas, various subtypes of prostatic carcinoma (PCa) are defined. They have specific clinicopathologic features, clinical relevance and prognosis. These subtypes are squamous cell, sarcomatoid, urothelial, basal cell, adenoid cystic, and small cell carcinoma. Small cell carcinoma of the prostate (SCCP) accounts for less than 0.5% to 2% of all malignant PCa and has different clinicopathologic features. SCCP usually accompanies adenocarcinoma of the prostate with a rate of approximately 50%. It is a very aggressive type of cancer and most cases are diagnosed at an advanced stage because of no concordant elevation of prostate-specific anigen (PSA). Most cases are diagnosed at advanced stage due to early metastasis. The bones, liver, and regional and distant lymph nodes are the most common sites of metastasis of small cell carcinoma of the prostate. Skin metastasis of small cell carcinoma of the prostate is a very rare entity due to the uncommon metastatic site. Here, we describe the case of a patient with small cell carcinoma of the prostate which metastasized to his skin.
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A 74-year-old Caucasian man presented to another urology center for mild lower urinary tract symptoms in 2003. His prostate-specific antigen was 23 ng/mL. According to the physical examination signs and prostate-specific antigen, he underwent a transrectal ultrasound-guided prostate biopsy. The pathologic examination of his prostate revealed a Gleason score: 3+4=7 adenocarcinoma of the prostate. Investigations showed stage T2N0M0 disease, and he was treated with radiotherapy to his pelvic lymph nodes and prostate. Six years after the initial diagnosis, he complained of a palpable left-side 2×2cm subcutaneous solitary mass localized just behind his scapula. The results of his laboratory tests, including serum acid phosphatase and prostate-specific antigen, were in normal ranges. Our general surgery department performed a diagnostic biopsy of the mass and totally excised the lesion. The pathologic examination of the mass showed small cell carcinoma metastasis with chromogranin + and the pathologist advised us to examine the lung or prostate for the primary tumor. The patient undertook a transrectal ultrasound-guided prostate biopsy and the pathologic result revealed small cell carcinoma within residual adenocarcinoma. We investigated the other sites for metastasis and restaging investigations showed a 1cm metastatic lesion in his liver. Our medical oncology department decided to treat him with combination chemotherapy with etoposide and cisplatin in six cycles; however, he died due to disseminated myocardial infarction before starting the fifth combination chemotherapy cycle.
The SCCP has an aggressive character and a tendency to metastasize early on to the liver, bones, bladder, rectum, central nervous system, lungs, distant and pelvic lymph nodes, and even the pericardium. Skin metastasis is a very uncommon phenomenon and there are only a few reports in the literature about metastasis of SCCP to the skin. The disease can be silent and its only manifestation might be symptoms associated with metastasis. For this reason, most patients are diagnosed when SCCP is at an advanced stage. The clinicopathologic features of SCCP are similar to small cell carcinoma of the lung (SCCL). Like in the lung, vascular invasion, high mitotic index, and necroses are common findings. Due to histologic similarity to SCCL, paraneoplastic syndromes can be observed in a minority of patients. These can be hyperparathyroidism, thyrotoxicosis, hypercalcemia, hyperglucagonemia, and Cushing’s syndrome.
The pathology of neuroendocrine differentiation of small cell carcinoma makes response to androgen deprivation therapy poor. Chromogranin A, a neuroendocrine marker, might be elevated if there is a neuroendocrine differentiation of the carcinoma. This marker is known to activate androgen receptors, even in the absence of androgens.
The mean survival of patients with SCCP ranges between 5 and 17 months and less than 5% of cases survive beyond 24 months. The treatment algorithm of SCCP is a dilemma in urology due to its rarity, aggressive nature, and uncommon features. The treatment of SCCP is similar to that of patients who have SCCL. As chemotherapeutic agents, cyclophosphamide, etoposide, doxorubicin, vincristine, and cisplatin with or without doxorubicin might be used for treating patients with SCCP. Other agents like carboplatin, gemcitabine and docetaxel have also been investigated in studies and showed benefits with acceptable tolerable adverse effects. The other treatment modalities of SCCP are surgery and radiation therapy. Radiation therapy might be considered for local control of the disease with chemotherapy. It has been also suggested that surgery could not be the proper treatment modality of SCCP due to the fact that most cases with SCCP have a distant metastasis at initial diagnosis.
Clinicians should keep in mind that early diagnosis of this disease is very difficult due to early metastatic spread of small cell carcinoma and lack of concordant elevation of PSA. There is no standard accepted treatment modality for his pathology, and overall diagnosis is poor.
Kursat Cecen, Mert Ali Karadag, Aslan Demir, and Ramazan Kocaaslan as part of Beyond the Abstract on UroToday.com. This initiative offers a method of publishing for the professional urology community. Authors are given an opportunity to expand on the circumstances, limitations etc... of their research by referencing the published abstract.
Kafkas University Faculty of Medicine, Department of Urology, Kars, Turkey