November 25, 2004

Metastasis of Breast Carcinoma to Intracranial Meningioma

A patient who had been treated for bilateral breast carcinoma subsequently developed a metastatic breast lesion in a meningioma. Although it is not uncommon for more than one tumor to occur in the same patient, metastases from one tumor into another tumor are rare ("tumor to tumor" phenomenon). Meningiomas are the most common primary, intracranial tumors to harbor metastases, the majority of which arise from breast and lung carcinomas. Patients with a history of breast cancer and a solitary, intracranial mass with radiological features consistent of meningioma should be evaluated surgically. The lesion may be a primary cerebral malignancy, a metastatic lesion, or a meningioma with or without a metastatic lesion.

Key words: Meningioma * Metastasis * Breast neoplasms.

Tumors of one origin rarely metastasize to tumors of another origin ("tumor to tumor" phenomenon).1 The most common tumor likely to harbor metastases from a second different tumor is a meningioma. The most likely sources of metastases to meningiomas are breast malignancies and lung malignancies. A metastasis into a meningioma is rarely accompanied by a metastasis into a normal part of the brain. A discussion of the characteristics which meningiomas may have and which may be attractive to metastatic, malignant breast cells is offered below.

Case report

A postmenstrual, 54-year-old woman who had suffered for 4 to 5 months from an ulcerating lesion located in the central and upper- outer parts of her left breast was found to have breast cancer. Mammography demonstrated a nodular, non-palpable lesion in the upper- outer quadrant of her right breast and, by fine needle aspiration cytology (FNAC), it also was diagnosed as a breast malignancy. No metastatic lesions were detected by bone scintigraphy, thoracic CT, and abdominal ultrasonography.

The administration of 5 courses of neo-adjuvant, systemic chemotherapy using 5-fluorouracil, cyclophosphamide, and epirubicin (FEC scheme) resulted in significant reduction of the cancer in her left breast. She then underwent bilateral mastectomies (Halstead radical mastectomy on the left and modified radical mastectomy on the right).

The pathological examination revealed bilateral, ductal invasive carcinomas. The left was staged G2 pT4b pNlbi (1/29). The right was staged G2 pTlc pNO (0/35). Estrogen and progesterone receptors were negative; C-erb was positive (40% of the cells on the left and 90% of the cells on the right).

Postoperatively the patient's left mastectomy field was treated with radiotherapy and she received 3 more cycles of chemotherapy (FEC scheme).

One year later, the patient reported that she had had a 10-day history of unstable ambulation, weakness of the muscles of her right lower limb, and paresthesia of the right upper limb. A neurologic examination objectively confirmed her symptoms. No signs of local or regional breast recurrences were detected.

Cerebral RMI demonstrated an extra-axial, rounded, 65 mm mass in a left fronto-parietal convexity. It had a low signal intensity (T1- weighted imaging). Infusion of contrast material enhanced the lesion (Figure T). Dynamic angiographic sequences detected pathological vascularization with a classic angiographie "mother-in-law" sign (i.e. tumor blush that arrives early and stays late), (Figure 2).

Figure 1.-Cerebral RMI: demonstration of an extra-axial, rounded, 65 mm mass in a left fronto-parietal convexity with low signal intensity suggestive of a meningioma.

Figure 2.-AngioRM: dynamic angiographie .sequences deled pathological vascularizaton with a classic "mother-in-law" sign (i.e. tumor blush that "arrives early and departs late").

Figure 3.-A fibroblastic, benign meningioma containing focal nicuistases of poorly differentiated breast carcinoma (Hematoxylin and eosin, 100).

Bone scintigraphy, thoracic CT, and ultrasonography of the abdomen, mastectomy scars, axillae, and supraclavicular fossae were unremarkable. Neither local nor regional recurrences nor other metastatic lesions were detected. Tumor marker was normal (CA 15.5) Pathological examination revealed a fibroblastic, benign meningioma containing focal metastases of poorly differentiated breast carcinoma (Figure 3).

Discussion and conclusions

Metastases from one tumor to another are rare. The criteria required to identify a true "tumor to tumor" phenomenon are:

1. existence of a malignant, primary tumor must he demonstrated;

2. a metastasis must be contained within a benign tumor;

3. the metastatic cells found in the benign tumor must be similar to those of the primary tumor. This case fulfills the above criteria.

Meningiomas are the most common, primary intracranial tumors that host metastatic cancers. About 50 cases have been reported in the medical literature.2 The metastases usually arise from breast malignancies (women) and lung malignancies (men).3, 4 Occasionally tumor to tumor metastases are reported as originating from malignant melanomas,5 myeloid leukemias associated with blastic crises,6 and cancers of the kidney, prostate, endometrium, parotid, thyroid, and esophagus.

Meningiomas visually show a uniform enhancement from contrast administration when studied by CT scan or MRI. CT scans may show non- enhancing areas in benign meningiomas if they contain cystic or necrotic changes. But, non-enhancing areas also appear when malignant rather than benign changes are present. MRI studies of cerebral metastatic lesions have shown hypodense areas, hyperdense areas, and densities similar to meningiomas.7 We have found no reports in the literature in which a correct diagnosis of a metastatic tumor to a meningioma has been made prior to the surgical removal and histological evaluation of the cerebral mass. It appears to be impossible at this time to designate any specific radiologie sign, which will accurately differentiate benign meningiomas from meningiomas harboring metastatic cells.

Reports describing the relationship between metastatic, breast cancer cells and meningiomas can be found in the medical literature. Epidemiological studies do not, however, uniformly support some authors' opinions that meningiomas and breast metastases attract each other.

Some explanations proposed to support the belief that a unique attraction exists between the 2 tumors include:

1. the 2 cellular populations demonstrate an augmentation of expression of similar oncogenes (c-myc);8

2. both tumors express hormone receptors and both can grow rapidly during pregnancy;9

3. the loss of tumor-suppressor gene, associated with syndromes of multiple primary tumor, often including the meningioma;10 and

4. the rich vascular supply and indolent growth of mengiomas may make them susceptible to seeding from extracranial tumors.

On the other hand, breast cancer metastases to meningiomas may simply be fortuitous because both tumors are relatively common in women in their 5th and 6th decades.11

In the clinical setting the onset of cerebral neurologic signs or symptoms in a woman previously diagnosed as having had a breast cancer requires that her diagnostic studies include an evaluation for the possibility of a metastatic cerebral tumor and for the possibility of a primaiy, malignant or benign cerebral tumor. Although single cerebral metastases from a breast cancer are relatively rare in the absence of widespread breast metastases, one should also evaluate a woman for a hidden, as yet undiagnosed, breast malignancy should a brain tumor be discovered in a woman who has not had a history of breast cancer.

Acknowledgements.-We would like to thank R. N. Sacco, MD, Portland OR, for his assistance with manuscript preparation.


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1 Moriggia Pelascini Hospital, Gravedona (Como), Italy

2 Departmen\t of Clinical and Biological Sciences Insubria University, Varese, Italy

Received March 26, 2004.

Accepted for publication July 15, 2004.

Address reprint requests to: G. M. Baratclli MD, Unit Operativa di Chirurgia, Ospedale di Gravedona, 22015 Gravedona (Como), Italy. E-mail: [email protected]

Copyright Edizioni Minerva Medica Jun 2004