PROSTATE CANCER WITH ISOLATED LUNG METASTASIS: AN UNUSUAL PRESENTATION

Abstract

TOPIC: Lung Pathology TYPE: Medical Student/Resident Case Reports INTRODUCTION: A solitary pulmonary nodule from metastatic prostate cancer without concurrent bone involvement is extremely rare. Although more than 40% of prostate cancer patients have pulmonary involvement on autopsy, less than 1% have isolated pulmonary metastasis [1]. Prostate cancer routinely metastasizes from prostate to bone before reaching the lungs and other organs at later stages [2]. We present a unique case of a solitary pulmonary nodule from metastatic prostate cancer in the absence of osseous, lymphatic, or other organ metastasis. To date, only 23 other similar cases have been reported throughout the world. CASE PRESENTATION: We present a case of a 78-year-old male diagnosed with prostate cancer in 2009 (Gleasons 6-Gleasons 8, PSA 13, T1CN0M0). Patient initially underwent definitive radiation therapy and androgen deprivation therapy (ADT) with bicalutamide. Total body CT and PET scans revealed no adenopathy and no other metastatic lesions. After multiple rounds of ADT and radiation, repeat prostate biopsies in 2012 and 2013 were both negative and PSA was undetectable. The patient was then placed on active surveillance. This uncovered a PSA elevation in 2014. At the time the patient was given treatment options, but he elected for conservative management by restarting ADT and undergoing further imaging. Chest CT scans were performed from 2014 to 2021 for surveillance. A chest CT scan in 2014 demonstrated no metastatic lesions, however in 2016 a solitary 11mm pulmonary nodule was discovered in the right upper lobe. This nodule enlarged to 16mm over the course of 4 years, which prompted further investigation. A primary pulmonary carcinoma was suspected due to a 15-pack-year smoking history and absence of metastatic lesions. However, CT-guided core biopsy of the right upper lobe revealed an adenocarcinoma consistent with prostate cancer metastasis. DISCUSSION: In patients with a solitary pulmonary nodule, primary lung carcinoma is much more likely (35%) than isolated lung metastasis from prostate cancer [3]. Isolated lung involvement in metastatic prostate cancer is extremely rare, with less than 1% found in autopsy [4]. We present a unique case of a solitary pulmonary nodule from metastatic prostate cancer in the absence of bone involvement. In a study with over 1,290 prostate cancer patients, 48 were found to have lung metastasis, while only 11 (0.86%) had pulmonary nodules [5]. CONCLUSIONS: Active surveillance with routine PSA checks and digital rectal exams are important for monitoring recurrence of prostate cancer. The addition of routine imaging and prostate biopsies may aid in earlier detection of recurrence and distant metastasis. Early detection of oligometastatic pulmonary nodules from prostate cancer may guide targeted therapy, such as with our patient that is undergoing targeted radiation. REFERENCE #1: Siegel RL, Miller KD, Jemal A. Cancer statistics, 2018. CA Cancer J Clin 2018;68:7-30. REFERENCE #2: Fornetti, J., Welm, A.L. and Stewart, S.A., 2018, Understanding the Bone in Cancer Metastasis. J Bone Miner Res, 33: 2099-2113. REFERENCE #3: Greenlee RT, Hill-Harmon MB, Murray T, et al. Cancerstatistics, 2001. CA Cancer J Clin 2001; 51:15–36 Reference #4: Saitoh H, Hida M, Shimbo T, et al. Metastatic patterns of prostatic cancer. Correlation between sites and number of organs involved. Cancer 1984;54:3078-84. Reference #5: Fabozzi SJ, Schellhammer PF, el-Mahdi AM. Pulmonary metastases from prostate cancer. Cancer 1995;75:2706-9. DISCLOSURES: No relevant relationships by Luke Dreisbach, source=Web Response No relevant relationships by Saad Fattouhi, source=Web Response No relevant relationships by Garo Kalfayan, source=Web Response No relevant relationships by Shahriyar Tavakoli, source=Web Response No relevant relationships by Vahe Zograbyan, source=Web Response