A 57‐YEAR‐OLD FEMALE WITH A CEREBELLAR MASS

CLINICAL HISTORY

A 57‐year‐old woman with past medical history of a uterine leiomyosarcoma was referred to the department of Neurology due to recurrent episodes of nausea and vomiting, as well as instability during walking. In particular, the patient had underwent a hysterectomy and oophorectomy 8 months ago. Neurological physical examination revealed disorientation, horizontal nystagmus, equilibrium imbalance and ataxia. On CT scan, an extra‐axial calcified mass, located in the left cerebellar hemisphere, accompanied with mild edema and measuring 4.5 cm in maximum diameter, was visualized (1, 2). A suboccipital craniectomy with segmental surgical excision of the lesion was subsequently performed.

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MICROSCOPIC PATHOLOGY

Histopathologic examination of multiple tissue fragments displayed infiltration of cerebellar tissue by pleomorphic neoplastic cells (3, 4). The neoplastic cells were mononuclear, with irregular, atypical nuclei and mildly eosinophilic cytoplasm (Figure 5). Mitotic figures were frequent. Tumor cells were immunoreactive for vimentin, desmin (Figure 6) and SMA (Figure 7), but not for GFAP, Neuron‐Specific Enolase (NSE), synaptophysin, S100 protein, cytokeratins AE1/AE3, LCA, CD99 and type IV collagen. The Ki‐67 proliferation (labelling) index was approximately 20%. What is the diagnosis?

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DIAGNOSIS: METASTATIC UTERINE LEIOMYOSARCOMA

Follow‐up CT scans designated the presence of residual tumour, measuring 2 cm in maximum diameter, while additionally displayed abundant metastatic foci both in the lungs and in the abdominal cavity. Adjuvant radiotherapy was introduced. The patient died of cardiopulmonary arrest 6 weeks after the removal of the metastatic tumor.

DISCUSSION

Leiomyosarcoma has been defined by the World Health Organization of Tumors as a malignant neoplasm composed of cells demonstrating smooth muscle differentiation and accounts for 25–36% of all sarcomas of the uterus and slightly over 1% of all uterine malignancies (10). Its aggressive biological behavior is associated to the strong tendency for recurrence, local spread and more often hematogenous dissemination. In fact, the majority of the tumors recur within 2 years from diagnosis and about 90% show distant metastases alone or in combination with pelvic recurrences (5).

Thorough review of the literature (including case reports and autopsy series) revealed 22 documented cases of brain and skull metastasis from uterine leiomyosarcoma 2, 4, 5, 6, 9. In decreasing order of frequency, the most common intracranial sites were the cerebrum (15 cases), skull (4), pons (1), sphenoid sinus (1) and cerebellum (1). A more complete discussion and bibliography can be found at (URL:)

Of particular importance is the fact that most patients developed pulmonary metastases; a well recognized phenomenon in patients with metastases of sarcoma to the brain. Some have suggested that uterine malignancy is disseminated hematogenously to the central nervous system (CNS) after lung invasion by pulmonary arterial circulation (3), with paravertebral venous system being a second possible route for metastasis.

Hematogenous spread of sarcoma to the CNS is quite uncommon. Alveolar soft‐part sarcoma, fibrosarcoma, leiomyosarcoma, osteosarcoma, malignant fibrous histiocytoma and rhabdomyosarcoma encompass the most frequent sarcoma types which metastasize to the brain 4, 9. Cerebellar metastases comprise approximately 15% of all CNS metastatic lesions in patients with systemic cancer, with the lung, breast and gastrointestinal tract being the most common primary sites. Metastatic sarcomas to the cerebellum are extremely rare; only 4 case reports have been previously published, including two osteosarcomas, one Ewing sarcoma and one uterine leiomyosarcoma 1, 2, 7, 8.

The main symptoms which accompany metastatic lesions are severe headache, gait disturbance and motor deficit. Cerebellar metastases are associated with worse prognosis than metastases in cerebral hemispheres due to obstructive hydrocephalus and brain stem compression. Neurosurgical removal of the lesion, followed by radiation therapy, is regarded as the best treatment for metastases to the cerebellum, regardless of the primary tumor histology (11).

To our knowledge, this is the second reported case of a uterine leiomyosarcoma metastatic to cerebellum, suggesting that hematogenous dissemination of this tumor plays a key role in the course of the disease. CNS metastasis is associated with dismal prognosis and stressing the importance of including this entity in the complete differential diagnosis of CNS lesions occurring in female oncologic patients.

ABSTRACT

A 57‐year‐old female presented with recurrent episodes of nausea and vomit, as well as instability during walking. The patient had a history of uterine leiomyosarcoma, for which she underwent a hysterectomy and oophorectomy 8 months ago. CT scan revealed a calcified mass that was located in the left cerebellar hemisphere which was resected. Histologically, multiple tissue fragments displayed infiltration of cerebellar tissue by polymorphic spindle‐shaped cells. The Ki‐67 proliferation index was approximately 20%. The morphological and immunohistochemical data, in association with the past clinical history, were consistent with cerebellar metastasis of uterine leiomyosarcoma. Although adjuvant radiotherapy was introduced, the patient died of cardiopulmonary arrest 6 weeks after the surgical procedure. The present case adds to the body of literature being the second report of uterine leiomyosarcoma metastatic to the cerebellum.