Case Report: Tumor-to-tumor metastasis: a rare case of prostate adenocarcinoma metastasis to lung squamous cell carcinoma in a patient with multiple primary malignancies

TL;DR

A rare case of prostate cancer metastasizing to a coexisting lung cancer is reported, highlighting an unusual tumor-to-tumor metastasis phenomenon.

Contribution

This case report documents a rare instance of prostate adenocarcinoma metastasizing to lung squamous cell carcinoma, adding to limited literature on tumor-to-tumor metastasis.

Findings

Prostate adenocarcinoma metastasized to a primary lung squamous cell carcinoma in a patient with multiple malignancies.

The lung mass was confirmed to contain both lung squamous cell carcinoma and prostate cell carcinoma upon pathological examination.

The case highlights the rare phenomenon of tumor-to-tumor metastasis with prostate cancer as the donor tumor.

Abstract

Tumor-to-tumor metastasis (TTM) is a rare occurrence in patients with two separate primary tumors, with the more malignant tumor more commonly metastasizing to a separate primary benign or low-grade tumor. Lung carcinomas are the most common metastatic tumor donors. However, the opposite phenomenon (lung carcinoma as a recipient of metastasis from prostate adenocarcinoma) is rarely previously reported in the literature. We report the case of TTM from prostate cancer to coexisting primary lung cancer.

The 69-year-old male patient underwent surgery for tongue cancer on March 16, 2024, during which a lung mass was discovered in the right lower lung. The lung mass increased in size by follow-up thoracic computed tomography scan on October 4, 2024. Subsequently, the patient underwent single-port thoracoscopic right lower lung lobectomy and mediastinal lymph node dissection. Postoperative pathological results revealed that the lung mass had two components: lung squamous cell carcinoma and prostate cell carcinoma. MRI evaluation and PSA tests confirmed a prostate mass on November 8, 2024. Further, ultrasound-guided transperineal prostate biopsy was performed, and the biopsy pathology indicated prostate acinar adenocarcinoma. Subsequently, the patient underwent robot-assisted laparoscopic prostatectomy.

This case report presents a rare and intriguing instance of TTM, specifically describing prostate adenocarcinoma metastasizing to a primary lung squamous cell carcinoma. The manuscript contributes valuable documentation to the limited literature on this rare phenomenon and is of potential interest to the oncology community.

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