Rare case of Prostate Adenocarcinoma After Primary THA ; a report

A rare case of Prostate Adenocarcinoma After Primary THA has been reported by Michael M. Kheir at hospital for Special Surgery, 535 East 70th Street, New York USA and colleagues. The case study has been published in the journal Arthroplasty Today.

The patient is a 67-year-old man with a past medical history of obesity (body mass index of 32.8), gastroesophageal reflux disease, hypertension, and visual impairment.

He presented to the outpatient orthopedic joint reconstruction clinic with the chief complaint of right hip pain. He had previously undergone a left THA in 2013, walking a mile every day until he started having insidious worsening of right hip pain over the prior 6 months.

On physical examination, the patient had an antalgic gait. He denied pain to the left hip. When examining his right hip, leg lengths were noted to be equal. The skin in the peri-incisional area was intact without cutaneous lesions. The patient denied tenderness over the right greater trochanter. The patient's right hip range of motion was markedly limited and consisted of full extension to 90 degrees of flexion, internal rotation of zero degrees, external rotation of zero degrees, abduction of 20 degrees, and adduction of zero degrees. The patient described significant groin and buttock pain with hip motion. His muscle strength was weak, and tone was normal. There was no instability of the joint. Neurologic and vascular examinations were normal.

Anteroposterior pelvis and cross-table lateral radiographs were obtained demonstrating severe degenerative joint disease with bone-on-bone apposition of the right hip. THA was performed without complication, and the patient's femoral head specimen was sent to pathology.

The patient progressed well with physical therapy and was discharged home on postoperative day 1.

Histopathologic examination was performed, and besides showing features of severe osteoarthritis, it also showed metastatic adenocarcinoma with morphologic features suggestive of prostate origin, including epithelial cells with prominent central nucleoli forming glands. An immunohistochemical stain for prostate-specific antigen (PSA) was strongly positive, while stains for CK7, CK20, CD20, and TTF1 were negative. These immunohistochemical findings provide additional support for the diagnosis of metastatic prostate adenocarcinoma.

Retrospective review of the preoperative imaging studies shows ill-defined areas of sclerosis in the femoral head and neck, but even with knowledge of the final diagnosis, the radiographic findings are consistent with osteoarthritis and are not suggestive of metastatic carcinoma.

The patient was immediately informed of the results by the surgeon, and at the patient's request, the diagnosis was confirmed with an outside pathologist. The patient was urged to speak to his internist as soon as possible and was referred to urology for further management. The patient was seen at his 6-week postoperative visit and was doing well from a surgical standpoint. At that time, he confirmed that he did not have a diagnosis of adenocarcinoma prior to his right THA, thus demonstrating that the pathology specimen was the first indication of prostate adenocarcinoma. His serum PSA had been 2.0 in 2019 and was found to be 13.0 after receiving the diagnosis of metastatic adenocarcinoma. No interim PSA levels had been obtained. Subsequent imaging studies by his oncologist have detected computerized tomographic evidence of metastases in the skull and rib. He is currently being treated by his oncologist with enzalutamide daily and leuprolide once a month, and his latest PSA level is 1.0.

The authors commented that this case emphasizes the importance of routine pathologic examination of femoral head specimens retrieved during total hip arthroplasty, particularly since this was a clinically unsuspected finding. Although cases like these are rare and the process of routine pathologic examination raises a concern for economic implications, a timely diagnosis of adenocarcinoma provides benefits for the patient, for which cost benefit ratios are difficult to quantify.

Further reading:

Diagnosis of Prostate Adenocarcinoma on Routine Pathology After a Primary Total Hip Arthroplasty

Michael M. Kheir, Thomas W. Bauer, Geoffrey H. Westrich.

Arthroplasty Today 15 (2022) 19-23

https://doi.org/10.1016/j.artd.2022.02.025