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"Medical Journeys" is a set of clinical resources reviewed by physicians, meant for the medical team as well as the patients they serve. Each episode of this journey through a disease state contains both a physician guide and a downloadable/printable patient resource. "Medical Journeys" chart a path each step of the way for physicians and patients and provide continual resources and support, as the caregiver team navigates the course of a disease.

This month: A noteworthy case study

When an 85-year-old man with no history of chronic disease or surgery presented to the emergency department with a distended abdomen, a painful swelling in his pelvis, and complaints of unaccountable fatigue, loss of appetite, and urinary symptoms, cancer was a key suspect for Zied Mahjoubi and colleagues at Hospital La Rabta in Tunisia.

As they reported in the , physical examination revealed a pelvic mass 15 cm in size with poorly defined margins attached to the wall of the abdomen, and digital rectal exam found the prostate to be enlarged and lumpy. Laboratory tests showed that the patient had hypochromic and microcytic anemia, with a hemoglobin of 9 g/dcl, and an elevated serum prostate-specific antigen (PSA) level of 300 g/mL.

Ultrasound examination showed the mass to be heterogeneous and lobulated, and "appeared to be partially liquefied by necrosis," the team wrote. The liver, spleen, and kidneys all appeared normal.

Computed tomography (CT) confirmed a "large lobulated necrotic pelvic and extraperitoneal mass with medial displacement of the bladder, causing mild bilateral hydroureteronephrosis," the authors stated. The mass was adjacent to the prostate, which was enlarged and calcified.

The patient also had numerous swollen periaortic and iliac lymph nodes, which ranged from 26 to 39 mm in size. "Bone scan showed suspicious lytic lesions of the right ischium and the posterior arch of the two upper sacral vertebrae," the team noted.

After a multidisciplinary consultation with a urologist, general surgeon, pathologist, and radiologist, the team arrived at an initial diagnosis of atypical pelvic lymphoma associated with prostate cancer metastasis, based on the presence of numerous enlarged retroperitoneal lymph nodes.

After an ultrasound-guided biopsy of the mass, immunohistochemical analysis found "eosinophilic cells with large hyperchromatic nuclei containing visible nucleoli and focal cytoplasmic with PSA staining, confirming a prostate adenocarcinoma Gleason 9."

The patient received a bilateral orchidectomy and recovered without complications. On follow-up examination 3 months later, his performance status had improved and his PSA level declined to 60 ng/mL, although the pelvic mass remained the same size.

Discussion

While metastatic prostate cancer is relatively common in older men, this particular patient represented a rare case of metastatic prostate cancer presenting as a large symptomatic pelvic mass mimicking lymphoma, Mahjoubi and colleagues explained.

Prostate cancer is routinely detected as a result of digital rectal exam findings and blood tests showing elevated PSA levels, and confirmed with histologic analysis of a prostate biopsy. Metastatic disease is generally assessed with magnetic resonance imaging (MRI) of the pelvis and bone scans.

This patient's diagnosis was unusual in that the disease presented with a compressive symptomatic pelvic mass mimicking a lymphoma or other disease. "Indeed, urologists may be confronted in their daily practice [by] patients suffering from large pelvic symptomatic masses," the authors wrote.

The large range of differential diagnoses, they explained, includes primary or secondary pelvic tumors of various etiologies, from bladder carcinoma and smooth muscle tumors to benign teratoma and fibrous malignant histiocytoma. Tumors resulting from inflammatory conditions, idiopathic retroperitoneal fibrosis, and lymphoproliferative disorders may also be included among diagnostic considerations.

Diagnosis of this patient's painful pelvic mass as Gleason 9 prostate adenocarcinoma makes it one of fewer than 30 reported cases, Mahjoubi and co-authors said. Since the first report in 1966 of a giant prostate cancer that presented as an abdominal mass, only 21 cases have been reported, of which about 80% were moderately and well-differentiated adenocarcinoma.

The patients in those reports were a mean age of 70.8 years, and most of the tumors were associated with abdominal pain and lower urinary tract difficulties. PSA levels ranged from 170 to 27,000 mg/mL, and the patients were followed for a mean of 10.2 months.

Imaging is central to the diagnosis of such pelvic masses and identification of complication risks, such as compression of adjacent structures. "MRI is indicated to determine the involvement of the seminal vesicles, bladder, and pelvic side walls, as well as pelvic and abdominal lymph nodes, for staging purposes," Mahjoubi and co-authors explained.

In this patient, the CT scan findings, along with significant involvement of retroperitoneal lymph nodes, suggested the diagnosis of atypical pelvic lymphoma, the team said. "Histological findings of the biopsy rectified the diagnosis and confirmed a metastatic prostate cancer that has already spread to bone and to multiple nearby and distant lymph nodes."

Metastatic prostate cancer is treated primarily with hormone therapy, the authors said, adding that luteinizing hormone-releasing hormone agonists have significantly decreased tumor volume in a few reported cases of giant prostate cancer. Similarly, external-beam radiation therapy has reduced prostate volume, with 60 Gy associated with a 96.7% shrinkage in one case of giant prostate tumor.

Among 39 patients receiving intensity-modulated radiotherapy with or without androgen deprivation, radiotherapy was independently associated with prostate shrinkage without any additional benefit with concomitant androgen deprivation, the case authors said. In their patient, surgical castration produced "a remarkable improvement" of performance status and a decrease of PSA to 60 ng/mL but without decrease of the pelvic mass on physical examination.

Conclusion

"Prostate cancer should be considered in the assessment of large pelvic masses," Mahjoubi and co-authors concluded. "Digital rectal examination and testing PSA levels can lead to the diagnosis. After histological confirmation, the androgen deprivation is the main treatment and radiotherapy is proven to help decrease tumor volume."

Read previous installments in this series:

Part 1: Prostate Cancer: Epidemiology, Diagnosis, and Treatment

Part 2: The Latest on Prostate Cancer Diagnosis

Part 3: The Real-Life Consequences of Controversies About PSA Testing