Tumor-to-Tumor Metastasis: Lung Adenocarcinoma as a Recipient of Metastasis from Renal Cell Carcinoma: A Case Report

Tumor-to-tumor metastasis: A case report of metastasis of nasopharyngeal carcinoma to meningioma and review of the literature

RATIONALE

Tumor to tumor metastasis is a rare phenomenon clinically, especially tumor to meningioma metastasis. Here, we present an unusual case of metastasis of nasopharyngeal carcinoma to meningioma.

PATIENT CONCERNS

A 55-year-old man, with a history of nasopharyngeal carcinoma, developed neurological symptoms.

DIAGNOSIS

Computed tomography and magnetic resonance imaging revealed a mass on left temporoparietal lobe, indicating the presence of meningioma. The pathologist diagnosed the metastasis of nasopharyngeal carcinoma (differentiated non-keratinizing squamous cell carcinoma) to meningioma.

INTERVENTIONS

Chemotherapy and immunotherapy were performed following the resection.

OUTCOMES

The patient has been well and no relapses has been observed.

LESSONS

Doctors should be aware of the presence of tumor-to-tumor metastasis, which is a rare phenomenon. A positive history of primary extracranial tumor should raise the suspicion of potential tumor-to-tumor metastasis.

Tumor-to-Tumor Metastases Involving Clear Cell Renal Cell Carcinomas: A Diagnostic Challenge for Pathologists Needing Clinical Correlation

Tumor-to-tumor metastasis is a rare event which it is specifically up to pathologists to bring to light correctly. The histological identification of such tumor-to-tumor cases is simple when the respective histologies are different but can be problematic if the case includes two carcinomas with similar cytoarchitecture viewed one inside the other under the microscope. We report four cases of this condition in which clear cell renal cell carcinoma is involved, either as a receptor or as a donor, and remark on the difficulties in recognizing some of them. Appropriate clinical-pathological correlation, including a review of the patient's antecedents and radiological exams, would be a great help in routinely identifying tumor-to-tumor metastases.

F-FDG18PET/CT incidental detection of tumor-to-tumor metastasis in patients investigated for squamous cell lung cancer

Tumor-to-tumor metastasis (TTM) is a well-known entity, although this is still an extremely rare phenomenon. The lung cancers are considered the most frequent metastatic donors while kidney cancers are the most common recipient. The finding of TTM is often incidental during a biopsy of metastases or on surgical specimens but never suspected on radiological assessment of tumor extension. The finding of an unexpected region of Fluorodeoxyglucose (FDG) uptake can occur when performing whole body Positron Emission Tomography/computed tomography (PET/CT) scan and potentially raises the possibility of a second primary tumor. However, PET/CT scan incidental detection of tumor-to-tumor metastasis has never been reported in English literature. We report here a case of clear cell renal carcinoma, receptor of metastases originating from an oligometastatic squamous cell lung cancer detected on the PET/CT scan performed as part of the extension workup. Morphological and immunohistochemical analysis of a percutaneous biopsy of the renal mass were consistent with the diagnosis of a metastasis of lung cancer into renal cell carcinoma. This is the first case of oligometastatic lung cancer with the occurrence of TTM suspected in PET/CT scan. Although this is a rare setting, it should be considered in daily practice, as it could potentially modify the oncological management offered to the patients.

Tumor-to-Tumor Metastasis: Renal Cell Carcinoma Metastasizing to a Lipoma of the Thigh: A Case Report

CASE

A 73-year-old man with a medical history significant for renal cell carcinoma (RCC) presented with widespread osseous metastases and imaging suspicious for RCC metastasizing to a lipoma interdigitated within the right vastus lateralis. The patient's pathological fractures were surgically addressed, and the lipoma excised. Final histology revealed a thigh lipoma involved by metastatic RCC without direct extension.

CONCLUSION

Tumor-to-tumor metastasis is a rare occurrence, with RCC typically being the most common "recipient" tumor. This is the first case to the best of our knowledge of RCC metastasizing to a lipoma, highlighting a rare phenomena in a patient with metastatic disease.