A donor neoplasm's hematogenous spread within a primary host tumor is known as tumor-to-tumor metastasis (TTM)

A donor neoplasm's hematogenous spread within a primary host tumor is knownas tumor-to-tumor metastasis (TTM) [1].

Though its exact pathophysiology is still unknown,TTM has been documented in the literature for nearly a century, since the first description by Fried in 1930 [2]. According to the literature, lung cancer and breast cancer are the most common donor tumors in TTM [3,4]. Here, we present our experience with a case of TTM of breast cancer to meningioma.

A 77-year-old female patient, known hypertensive, presented with insidious onset and gradually progressive diminished vision in left eye resulting complete loss of vision over a span of 10 days. Patient also had history of appetite loss and weight loss for 1 month with no history of seizures / vomiting / loss of consciousness. On MRI brain, a left Spheno-cavernous extra axial space occupying lesion was seen with edema and mass effect suggestive of meningioma (Figure 1a). Excision of the tumor mass was done and sent for histopathological examination which revealed a relatively circumscribed nodular meningeal tumor which was extensively infiltrated and effaced by an adenocarcinoma in tubules and nests (Figure 1b and 1c). Periphery showed nests/lobules of appreciable meningothelial tumor component with syncytial arrangement and occasional psammomabodies (Figure 1d).

On IHC analysis (Figure 2), Adeno carcinoma component was positive for panCK, CK7, EMA, GATA3, TRPS1, ER (>90%; strong intensity) and PR (>90%; strong intensity) while being negative for TTF1, CK20, S100 and Her2neu (score 0). This immunopurified favored a breast primary tumor. On taking deep history, patient was an operated case of breast cancer (25 years back).

Meningioma component was positive for Vimentin, S100(focal), EMA and PR while negative for others.

Ki67 index is Lessthan5Percentage in Adenocarcinoma componentand Lessthan1Percentage in meningioma component. Patient was advised for follow up PET-CT and radiotherapy was planned.

TTM refers to tumor cells that metastasize via the blood to a primary host tumor (recipient tumor) from a donor tumor [4]. TTM is a known phenomenon. Over 70Percentage cases involved meningiomas, of which nearly half showed breast cancer metastasis [5]. According to Paget's "soil and seed" theory, meningiomas are susceptible to becoming recipient tumors because of their high collagen and lipid content, which creates an optimal environment for implantation [6]. Campbell et al. laid down the criteria (Box 1) for TTM which is fulfilled in our case[7].

We present a rare case of TTM of breast cancer into a meningioma, which was treated using surgical resection. In the context of a meningioma, it is crucial to consider the potential for TTM in a patient with a systemic cancer. Further research is necessary to determine an appropriate course of treatment and prognosis for this uncommon occurrence, as the clinical significance of TTM is still unknown.

Acknowledgement 

None.

Conflict of Interest

None Declared.

Funding Sources

None.

Data Availability Statement

The data will be available on request from the corresponding author Informed Consent and Ethics Statement: Adequate informed consent has been taken from the patient and this manuscript has been approved by the institutional review board.