A 14‐YEAR‐OLD GIRL WITH MULTIPLE TUMORS

Clinical History and Neuroimaging

A 14‐year‐old girl with a recent history of sciatica and ataxic gait was admitted to the hospital. Brain and spine MRIs revealed a mildly heterogeneously contrast‐enhancing mass with a cystic component in the 4th ventricle with caudal extension through the foramen of Magendie with compression of the medulla (Figure 1A). Another cystic mass with a large enhancing nodule was detected in the left cerebellar hemisphere (Figure 1B). The spinal MRI revealed an extensive septated syrinx as well as an intramedullary contrast‐enhancing nodule at T4 (Figure 1D). Diffuse leptomeningeal enhancement with scattered nodules was visible in the suprasellar cistern, internal auditory canals, interpeduncular fossa, the ventral brainstem as well as the spinal cord. Moreover two solid, contrast‐enhancing lesions were detected in the right temporal lobe (Figure 1C); and in the sacral spinal cord, a “drop” metastasis was detected within the thecal sac (Figure 1E). A specific radiological diagnosis was not achieved. Multiple biopsies of the cerebellar lesion and of the tissue in the thecal sac were performed.

Figure 1.

‪

Microscopic Findings

Histologic examination of all biopsies showed a pleomorphic tumor mainly composed of spindle‐shaped cells intermingled with multinucleated giant cells and large cells with a pleomorphic nuclei (Figure 2A). Many eosinophilic granular bodies were also present, whereas cytoplasmic vacuolization were rarely observed (Figure 2B). There was a widespread dense intercellular reticulin network as well as perivascular lymphocytic infiltrates. Neither necrosis nor microvascular proliferation were observed. Immunohistochemically, many tumor cells were positive for GFAP (Figure 2C). Isolated cells or focal clusters of cells were also positive for neurofilaments and NEU‐N (Figure 2D). Furthermore, immunohistochemical analysis for CD34 revealed either a membranous pattern in some cells or a strong immunoreaction in a pericellular stromal pattern reminiscent of the reticulin network demonstrated by Gomori silver impregnation. Ki67 proliferative index did not exceed 2% and p53 was normal. What is the diagnosis?

Figure 2.

‫

Diagnosis

Multicentric pleomorphic xanthoastrocytoma (PXA; WHO grade II) with leptomeningeal dissemination.

Discussion

Pleomorphic xanthoastrocytoma (PXA) was first described by Kepes and colleagues in 1979 4. PXA is a rare neoplasm (to date, about 200 cases have been reported), accounting for less than 1% of astrocytic tumors that occurs on the surface of cerebral hemispheres of children and young adult 2. Typically, these tumors have a favorable prognosis and seizures are the most common presenting symptoms. Commonly, the site of presentation is supratentorial, but cerebellar lesions have also been described, mainly involving the cortex and leptomeninges 2, 3.

Histological features include marked cellular pleomorphism, variable cell lipidization, an abundant reticulin network and perivascular inflammatory cells. Although PXA appears malignant at first glance, mitosis and necrosis are usually absent. As a result, this nosological entity has been classified as a grade II tumor according to the WHO grading system, although an anaplastic variant and malignant potential have been described 1, 2, 5.

To our knowledge, this is the third case of typical PXA with disseminated disease reported in the literature 6, 7. Two other cases have been reported with leptomeningeal dissemination 6, 7 and only one case of metachronous multicentric PXA (in which lesions manifest themselves in succession after variable disease‐free intervals) has been described 7. Our case is the first and the only one in which a disseminated and synchronous multicentric PXA has been observed. Hence, it was considered important to describe this unusual case in order to add further information regarding the spectrum of the presenting clinical features of this rare neoplasm.

Even the biological indolent behavior of PXAs, these cases should alert physicians that unusual subdural and multicentric dissemination could be observed in PXA patients.

Abstract

Pleomorphic xanthoastrocytoma (PXA) is a rare astrocytic tumor that usually occurs in the superficial cerebral hemispheres of children and young adult and has a favorable prognosis. We report a case of a 14‐year‐old girl with a recent history of sciatica and ataxic gait. Pre‐ and post‐contrast brain and spinal MRI revealed the presence of multiple solid lesions with a cystic component in the cerebellum and the spinal cord with a concomitant massive leptomeningeal involvement Histological and immunohistochemical findings were concordant with a final diagnosis of WHO grade II PXA. Even the biological indolent PXAs' behavior, this is the third report in the literature of such an unusual multicentric PXA with leptomeningeal dissemination.