A mixed choroid plexus papilloma and ependymoma

Diagnostic dilemma: Papillary third ventricular neoplasm with concurrent choroid plexus and ependymal features in a cat

A 6-year-old, castrated male, domestic shorthair cat with progressive neurologic signs underwent magnetic resonance imaging, revealing a suprasellar mass, which resulted in euthanasia. Grossly, a tan-red tumor expanded the ventral third ventricle, compressed adjacent brain structures, and emerged ventrally at the midline. Histologically, numerous arborizing papillary formations protruded into a network of anastomosing luminal canals. Neoplastic cells immunolabeled for pan-cytokeratin, vimentin, and E-cadherin, and lacked immunolabeling for oligodendrocyte transcription factor 2 (OLIG2), glial fibrillary acidic protein (GFAP), and adrenocorticotropic hormone (ACTH). Transmission electron microscopy revealed apical microvilli, apical and lateral tight junctions, and a basal membrane. In this cat, the neuroanatomic location with ventral brain invasion was more suggestive of ependymal origin; however, there were overlapping histologic and immunohistochemical features, and ultrastructural features were more consistent with choroid plexus epithelium. Dual ependymal and choroid plexus differentiation could not be excluded. This case highlights species differences in both the occurrence and neurolocalization of intraventricular tumors in domestic animals and comparable features between papillary ependymoma and choroid plexus papilloma.

Psammomatous calcifications in thyroid oncocytic (Hürthle cell) follicular tumors

Concentric calcifications, also known as psammoma bodies, are a relatively frequent finding in certain types of tumors, particularly papillary thyroid carcinoma (PTC). In the thyroid, they have been assigned a significant role in the diagnosis of PTC and in distinguishing between these tumors and other types of thyroid neoplasms. Concentric calcifications have also less commonly been noted in other processes in the thyroid, such as in tumors characterized by cells containing abundant oxyphilic cytoplasm (i.e., Hürthle cells). We have studied 12 patients with oncocytic thyroid follicular tumors that contained scattered psammomatous calcifications that led to difficulties in diagnosis. The patients were 9 women and 3 men, aged 34 to 63 years. 10 cases corresponded to benign, non-invasive oncocytic tumors and 2 cases were minimally invasive follicular carcinomas of oncocytic (so called Hürthle cell) type. The psammomatous calcifications were randomly scattered throughout the lesions and were present as a focal, incidental finding in 8 cases and were diffuse in 4 cases. They were composed of concentrically laminated deposits of dense basophilic material closely resembling psammoma bodies, often associated with more homogeneous deposits of lightly eosinophilic material without concentric lamination that were interpreted as precipitated thyroglobulin. Seven patients with clinical follow-up, including one with minimally invasive carcinoma, were alive and well between 5 and 12 years after diagnosis. Concentric laminated calcifications may be encountered in oncocytic (Hürthle cell) follicular tumors and should not be interpreted as indicative of PTC in the context of oncocytic neoplasms of the thyroid.

CT and MRI findings of intra-parenchymal and intra-ventricular schwannoma: a series of seven cases

Objective

To analyze the computed tomography (CT) and magnetic resonance imaging (MRI) features of patients with intra-parenchymal and intra-ventricular schwannoma.

Methods

The CT and MRI features of seven cases with intra-parenchymal and intra-ventricular schwannoma were analyzed retrospectively.

Results

There were four men and three women (median age, 25 years; range, 12–42 years) in this study. The median tumor size was 4.4 cm (range, 3.1–6.5 cm). The mass was, respectively, round in four cases (57.1%), lobulated in two cases (28.6%) and oval in one case (14.3%). All tumors were well-circumscribed. Septa in the mass could be observed in three cases (42.9%), and nodular calcification was observed in two cases (28.6%), which peritumoral edema (n = 3, 42.9%) and hydrocephalus (n = 3, 42.9%) could be observed. Most of these lesions (n = 6) presented iso-hypointensity on T1-weighted images and iso-hyperintensity on T2-weighted images, except one lesion showing low intensity on T2WI. In addition, a fluid–fluid level was observed in one case. After contrast agents’ injection, all masses illustrated heterogeneously moderate to marked enhancement.

Conclusions

A well-defined solid and cystic mass with calcification and moderate to marked delayed enhancement may be an objective account of intra-parenchymal or intra-ventricular schwannoma.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12880-022-00917-z.

Posterior fossa choroid plexus papilloma with focal ependymal differentiation in an adult patient: A case report and literature review

Choroid plexus papillomas (CPPs) are rare neoplasms classified as World Health Organization grade I tumors. CPPs containing other tissues have occasionally been documented in the literature. However, few of these previous reports have provided clinical and radiological information. We herein report a case of a posterior fossa CPP with focal ependymal differentiation in a 42-year-old woman who presented with a 6-month history of progressive headache. Preoperative radiological images showed a hypervascular tumor protruding into the left foramen of Luschka with perilesional edema. Gross total resection of the tumor was performed. Histopathological examination revealed that the tumor was composed of papillary structures. Immunohistochemical staining of glial fibrillary acidic protein was focally positive around the capillaries, which was suggestive of “perivascular pseudorosette” formation. Our case showed similar imaging appearances as those of CPP; thus, it seems difficult to distinguish CPP with versus without ependymal differentiation by clinical and radiological features alone. The clinical significance and pathogenesis of ependymal differentiation in CPP remain unclear, and further case reports are required.