Sarcomatoid carcinoma is a biphasic tumour which is clinically aggressive, presenting with high stage and which has poor prognosis [2].
Patients with sarcomatoid carcinoma tend to be older men, with a mean age of 68 years and a range of 32–91 years [1].
More than half of the patients gives a history of prior acinar prostatic adenocarcinoma and usually 9–22 years after initial diagnosis, the tumour evolves to sarcomatoid carcinoma [2] and most of the patients provide a history of prior treatment by androgen deprivation and/or radiotherapy [1,2,3]. A case report giving a much shorter interval of, 08 months, evolving from acinar adenocarcinoma to sarcomatoid carcinoma after treatment with androgen blockage therapy is being reported by Onur et al. [5] Transformation of the acinar adenocarcinoma is thought to represent dedifferentiation from usually high-grade acinar prostatic adenocarcinoma [2]. Reason for the sarcomatoid transformation of this patient cannot be determined as he did not have such a therapeutic history.
The commonest presenting complaint of prostatic adenocarcinoma is LUTS [5]. Some other patients may present with low back pain, parasthesia and numbness of lower extremities due to locally advanced disease or metastatic disease. Absence of such symptoms predisposes the patients to late presentation with disseminated disease. Lack of expression of usual symptoms of prostatic carcinoma has resulted in diagnostic delay in this patient.
Many patents with sarcomatoid variant are unable to raise serum PSA levels, which contradicts the norm of acinar adenocarcinoma [5], and which causes diagnostic delays. Contrary to that norm, this patient had a raised serum PSA value. Should it be owing to the widely disseminated disease or this patient being belonging to the minority who expresses high serum PSA value is not clear.
Sarcomatoid carcinoma grows locally and metastasizes at distal sites in a quite short period of time [5], showing off its aggressive behaviour. Lymph node chains that are usually considered to be metastatic in prostate cancer are the common iliac, inguinal, femoral, aortic or other distant nodal chains [6]. Abdomino-pelvic together with supradiaphragmatic lymphadenopathy can present a diagnostic challenge, given the overlapping clinical and radiological differential diagnosis of lymphoma and other malignancies of numerous primary sites. Rare case reports of prostatic adenocarcinoma with cervical lymph node metastases as the first clinical manifestation of prostate cancer are found, in the setting of widely disseminated disease [7], but none of them were of sarcomatoid carcinoma. In turn, patchy positivity of the lymph node deposit for IHCm PSA made it more difficult, as usually deposits of prostate carcinoma show diffuse strong positive staining of the tumour cells. Several investigations including upper gastrointestinal endoscopy and chest X-ray were also performed, to reveal a primary site in the supradiaphragmatic region, as cervical lymphadenopathy was commoner in deposits of such primary locations. USS of thyroid gland was radiologically unremarkable. Krieken et al. have reported that salivary gland tumours in males have shown to be positive with IHCm PSA [8], but the USS did not reveal a salivary gland tumour either in this patient.
Osseous bone deposits on imaging studies are detected in over 65% of men with advanced prostate carcinoma [6]. The imaging studies of this patient also suggested similar findings which favoured primary prostatic tumour.
Microscopic appearance of the sarcomatoid carcinomas exhibits either biphasic pattern or monophasic pattern [2]. In biphasic tumours, the microscopic appearance of the prostate biopsy usually associates with a high Gleason grade of the carcinomatous component [2]. Similarly, the epithelial component, although a minute fraction of < 1% of the entire core of tissue in this patient’s prostate biopsy, was Gleason’s grade 5. The sarcomatoid component was the predominant morphological pattern, which showed a nondescript spindle cell population, without heterologous elements. Immunohistochemistry profile of the prostate biopsy was different from that of a usual acinar adenocarcinoma. Staining with IHCm cytokeratin, AE1/AE3, associated with negative staining with the prostate-specific marker, PSA, was challenging in confirming primary prostatic carcinoma, especially with the limited tissue in core biopsy obtained only for the confirmation of the presence of primary prostatic adenocarcinoma. However, this pattern of staining for IHCm was observed in previous case reports [3] and this is an expected staining pattern of this tumour [2]. IHCm NKX 3.1, the expression of which is highly sensitive [1, 2], and specific for prostatic adenocarcinoma [1], which would have been helpful in this situation for confirmation, was not available in the local setting. At this point, correlation with the serological and radiological findings was helpful in confirming the primary prostatic carcinoma. It was identified as sarcomatoid carcinoma, differentiating from other malignant spindle cell tumours of prostate, e.g. prostatic stromal sarcoma, prostatic leiomyosarcoma and prostatic solitary fibrous tumour, by the positive staining of these cells for cytokeratin stain. Therefore, and also because of limited availability of the tissue, other markers, which usually seem to be positive with the sarcomatoid component, e.g. Vimentin, Desmin, SMA and S100 [2], were not performed. Histomorphology of the cervical lymph node was suggestive of primary prostate cancer. It showed only the epithelial morphology and did not show a sarcomatoid component. This is the experience of most of the other documented metastatic sarcomatoid carcinomas of the prostate in the literature [2]. The patchy but strong staining of the tumour cells for IHCm PSA favoured deposit from prostate primary. This pattern of PSA staining is expected in the epithelial component of sarcomatoid carcinoma [2]. Molecular studies of ERG rearrangements detectable by FISH or sequencing in both sarcomatoid and carcinomatous components can be used to confirm sarcomatoid carcinoma as well as its origin in prostate gland [9], in cases in which the other modalities for diagnosis are equivocal. This is supported by another study which has revealed the presence of ERG fusions in this cancer [9, 10]. However, molecular studies were not needed in this patient as the clinical, radiological and serum investigations were in keeping with the primary prostate carcinoma.
Prognosis is often poor with a 5-year cancer-specific survival rate of 40% in organ confined disease [1]. However, in metastatic disease, like that of this patient, the predicted survival is 07 months [2]. A recent study suggests that local sarcomatoid prostate cancer can be effectively treated with definitive therapy leading to favourable outcomes [11], highlighting the importance of early detection.
