Rectal carcinoid tumor metastasis to a skull base meningioma

Confirmation of Intracranial Neuroendocrine Metastasis Using 68Ga-DOTATATE PET/CT

Neuroendocrine tumors (NETs) are rare neoplasms with an exceedingly low incidence of intracranial metastasis. We present a 79-y-old woman with a biopsy-proven pulmonary neuroendocrine tumor who presented with an intracranial mass in the posterior fossa that was avid on ⁶⁸Ga-DOTATATE PET/CT, facilitating the rare diagnosis of intracranial NET metastasis. The case highlights the utility of advanced imaging techniques in differentiating intracranial NET metastasis from other etiologies.

Cerebellopontine angle metastasis of a neuroendocrine tumor mimicking vestibular schwannoma: A case report

Background:

Neuroendocrine tumors (NETs) are uncommon neoplasms arising from neuroendocrine cells and are rarely associated with intracranial metastases.

Case Description:

We discuss the case of a 74-year-old woman with a right CPA tumor. She had a history of retroperitoneal NET, but was diagnosed with vestibular schwannoma due to a right-sided hearing loss and a right CPA tumor along the VII and VIII nerves. After a 3-year follow-up, she presented with repetitive vomiting, a 1-month history of gait instability, and a 3-month history of general fatigue. Brain imaging revealed tumor growth and edematous changes in the right cerebellum. She underwent retrosigmoid craniotomy and partial resection. Histopathological examination revealed metastatic NET. She underwent stereotactic radiosurgery for residual lesion and, at 11 months of follow-up, the lesion was confirmed to have shrunk on magnetic resonance imaging (MRI).

Conclusion:

This is the first case to report the natural course of cerebellopontine metastasis of a NET. The differential diagnosis of CPA tumors is diverse, and, in our case, we suspected a vestibular schwannoma because of the typical symptoms and imaging features. However, the tumor grew relatively faster than expected and showed intratumoral hemorrhage during the 3-year follow-up. Therefore, in patients with a history of a NET, a careful follow-up is advisable even for lesions highly suspected to be another benign tumor on MRI. Careful follow-up imaging and appropriate treatment strategies were useful to manage the brain metastasis. Although NETs metastasizing to the CPA are extremely rare, this possibility should be considered when patients with NETs have intracranial lesions.

Intrameningioma metastasis: A case-based literature review

A tumor-to-tumor metastasis inside a meningioma is a rare phenomenon. Malignant neoplasms of the breast and lung are the most common primary tumors. Other sites of origin include prostate, renal and gastric neoplasms. The included case files were retrieved from the medical records of the University Hospital of Crete, Greece. A review of the literature was conducted in March 2020 via PubMed. Relevant search results were few. We report a case of a 66-year-old female, with known Small Cell Lung Cancer, who presented with left-sided hemiparesis. The Magnetic Resonance Imaging scan revealed a right frontal extra-axial mass. The patient underwent a craniotomy and a gross total removal of the tumor. Histological examination of the excised mass revealed metastatic adenocarcinoma deposits inside a meningioma: tumor-to-tumor metastasis. Reviewing the available literature, it has been hypothesized that the following factors play a role in the pathophysiology of this phenomenon: progesterone and estrogen receptors, cell-to-cell adhesion molecules, rich vascularization, favorable metabolic, micro-and immunological environment. Meningiomas seem to be the most common type of intracranial neoplasm to host a metastasis. There is a difference between tumor-to-tumor metastasis and collision tumors. The former implies a recipient role of the host tumor, and the latter refers to a co-localization of two different tumors that grow into one another, both being in the same organ. Tumor-to-tumor brain metastasis is a well-described phenomenon but with unclear pathophysiology. Deeper knowledge could be beneficial for its management.

Metastases to meningioma-review and meta-analysis

PURPOSE

Meningiomas are a common tumor within the cranial cavity. They may be a target for metastatic spread of cancer elsewhere in the body. We analyzed all the data in the literature about tumor-to-meningioma metastasis (TTMM).

METHODS

We performed a meta-analysis using the PRISMA checklist to locate all cases of TTMM in the PubMed and Medline databases. We collected patient and cancer parameters, meningioma parameters, and clinical factors.

RESULTS

We located 124 articles, describing 152 cases of patients with TTMM. The mean (± SD) age of all patients was 62.21 ± 10.8 years, with even distribution above and below the mean. Of the cases, 65.9% were reported in women. The most common cancer origins of TTMM were breast and lung carcinoma, followed by kidney, prostate, and GI tract carcinoma. Cancer status is not a good marker of TTMM when managing a meningioma. In 36.69% of cases, TTMM was the presentation of an unknown cancer. In nearly 60% of the known cases, cancer was considered in remission for at least 1 year. Meningioma parameters are unhelpful when considering a TTMM. The distribution of meningioma location is similar to other series of meningioma reported in the literature. Meningioma grade is similar to meningiomas without TTMM. In 57.89%, the patient presented with a focal deficit. Presenting factors were seizures, elevated ICP, and others. Over 95% of cases were symptomatic at presentation.

CONCLUSION

TTMM should be suspected in cases of meningioma in a patient with background cancer, regardless of meningioma parameters or cancer status.

A Comparative Report on Intracranial Tumor-to-Tumor Metastasis and Collision Tumors

BACKGROUND

The incidence of 2 distinct tumor types occupying the same anatomic location is rarely observed and may be accounted for by 2 separate mechanisms: tumor-to-tumor metastasis and collision tumors, where 2 adjacent tumors invade one another. These rare phenomena arise from distinct mechanisms, which may affect their preoperative recognition, surgical approach, and postoperative care. We review 2 cases, highlighting their identification and perioperative management.

CASE DESCRIPTIONS

In case 1, a 71-year-old patient with a history of sphenoid wing meningioma presented with headache, nausea, and vomiting and was found to have a mass with meningioma and glioblastoma (GBM) characteristics. In case 2, a 61-year-old man with worsening dysmetria in the setting of unintentional weight loss presented with multiple masses in the pelvis, abdomen, lung, and brain. The brain masses were classified as meningioma with intratumoral metastatic adenocarcinoma foci.

CONCLUSIONS

Preoperative recognition of collision tumor and tumor-to-tumor metastasis is imperative for surgical planning, including selecting regions for tissue biopsy and goals of care. Meticulous evaluation of history and imaging and thorough pathologic analysis allow for effective diagnosis and optimal patient outcomes.