Opsoclonus myoclonus ataxia syndrome, ovarian teratoma and anti-NMDAR antibody: an 'unresolved' mystery.

Background: Opsoclonus-myoclonus-ataxia syndrome (OMAS) is characterised by the combination of opsoclonus and arrhythmic action myoclonus with axial ataxia and dysarthria. In adults, a majority are paraneoplastic secondary to solid organ tumours and could harbour antibodies against intracellular epitopes; however, certain proportions have detectable antibodies to various neuronal cell surface antigens. Anti-N-methyl-D-aspartate (NMDAR) antibodies and ovarian teratomas have been implicated in OMAS. Methods: Report of two cases and review of literature. Results: Two middle-aged women presented with subacute-onset, rapidly progressive OMAS and behavioural changes consistent with psychosis. The first patient had detectable antibodies to NMDAR in the cerebrospinal fluid (CSF) alone. Evaluation for ovarian teratoma was negative. The second patient had no detectable antibodies in serum or CSF; however, she had an underlying ovarian teratoma. Patient A was treated with pulse steroids, therapeutic plasma exchange (TPE) followed by bortezomib (BOR) and dexamethasone, while patient B was treated with steroids, TPE followed by surgical resection of ovarian teratoma. Both patients had favourable outcomes and were asymptomatic at the 6 monthly follow-up. Conclusions: With coexistent neuropsychiatric manifestations, OMAS can be considered a distinct entity of autoimmune encephalitis, pathogenesis being immune activation against known/unknown neuronal cell surface antigens. The observation of absence of anti-NMDAR antibody in patients with teratoma-associated OMAS and vice versa is intriguing. Further research on the potential role of ovarian teratoma in evoking neuronal autoimmunity and its targets is required. The management challenge in both cases including the potential use of BOR has been highlighted.

Growing Teratoma Syndrome-A Clinicoradiological Series.

Context Growing teratoma syndrome (GTS) is a rare entity seen following chemotherapy for metastatic nonseminomatous germ cell tumors, characterized by increase in size of the metastatic deposits, with normal serum tumor markers. Aims In this article, we aim to describe the various clinicoradiological presentations of GTS treated at our center. Design All patients who satisfied the GTS criteria from 2001 to 2019 were included. Characteristic imaging appearances along with sites of primary lesion and metastatic disease, stage and risk stratification at diagnosis, details of chemotherapy, details of surgical treatment and histopathology, levels of tumor markers, serum ß-human chorionic gonadotropin, lactate dehydrogenase, and alpha fetoprotein levels at baseline and at the end of all chemotherapy were analyzed. Results The significant radiological findings observed were an increase in the fat and cystic components and appearance of coarse calcifications within the lesions. Majority of the cases were male patients (87.5%) with testicular primaries and GTS transformation in nodal metastases being the most common occurrence (75%). All eight cases (100%) showed an increase in size and cystic component, whereas four out of eight cases (50%) had presence of internal septations and internal calcification. Conclusion Early recognition of this entity and clinical decision making through serial radiological imaging are of utmost importance as these growing deposits are resistant to chemotherapy and radiotherapy, with complete surgical excision being the only curative and definitive treatment option.

Special AT-rich sequence-binding protein 2 (SATB2) in the differential diagnosis of osteogenic and non-osteogenic bone and soft tissue tumors.

BACKGROUND: The diagnosis of osteosarcoma (OSA) depends on clinicopathological and radiological correlation. A biopsy is considered the gold standard for OSA diagnosis. However, since OSA is a great histological mimicker, diagnostic challenges exist. Immunohistochemistry (IHC) can serve as an adjunct for the histological diagnosis of OSA. Special AT-rich sequence-binding protein 2 (SATB2) was recently described as a reliable adjunct immunohistochemical marker for the diagnosis of OSA. METHODS: We investigated the IHC expression of SATB2 in 95 OSA and 100 non-osteogenic bone and soft tissue tumors using a monoclonal antibody (clone EPNCIR30A). The diagnostic utility of SATB2 and correlation with clinicopathological parameters were analyzed. RESULTS: SATB2 IHC was positive in 88 out of 95 cases (92.6%) of OSA and 50 out of 100 cases (50.0%) of primary non-osteogenic bone and soft tissue tumors. Of the 59 bone tumors, 37 cases (62.7%) were positive for SATB2, and of the 41 soft tissue tumors, 13 cases (31.7%) were positive for SATB2. The sensitivity of SATB2 as a diagnostic test was 92.6%, specificity 50%, positive predictive value 63.8%, and negative predictive value 87.7%. CONCLUSIONS: Although SATB2 is a useful diagnostic marker for OSA, other clinical, histological and immunohistochemical features should be considered for the interpretation of SATB2.