Relapsing Anti-MOG Antibody-associated Disease following COVID-19 Vaccination: A Rare Case Report and Review of the Literature.

Anti-myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) is an autoimmune demyelinating disorder that mainly occurs post-infection or post-vaccination. MOGAD after inoculation with coronavirus disease 2019 (COVID-19) vaccines is rare, and we herein report a rare case of a patient with MOGAD after vaccination using the Pfizer-BioNTech COVID-19 vaccine (BNT162b2, Pfizer Japan, Tokyo). Our report highlights the fact that MOGAD following inoculation with COVID-19 vaccine may show clinical relapse during reduction of the oral steroid dose, and continuous treatments with immunological agents is needed to prevent disease recurrence.

[A case of anti-MuSK positive MG with recurrent right-sided heart failure as the initial manifestation].

We report a case of anti-MuSK antibody (Ab)-positive myasthenia gravis (MG) in a patient who developed recurrent right-sided congestive heart failure. The patient presented with right-sided congestive heart failure of unknown etiology, necessitating hospitalization on three occasions over a 6-month period. During the third episode of hospitalization, she developed disturbance of consciousness, and heart failure was attributed to carbon dioxide narcosis. We performed various investigations including an anti-MuSK Ab assay, which showed positive results, and she was diagnosed with MG based solely on anti-MuSK Ab positivity. Selective plasma exchange did not produce a satisfactory therapeutic effect, and she received additional intravenous immunoglobulin, plasmapheresis, and oral immunosuppressive therapy after which she was successfully weaned off the ventilator. This case report highlights the following points: (a) Recurrent right-sided congestive heart failure may be the first manifestation of anti-MuSK Ab-positive MG and, (b) detection of the anti-MuSK Ab alone is a convincing rationale to diagnose patients with MG.

[A case of lumbar myxopapillary ependymoma discovered due to headache].

A 23-year-old man was admitted to our hospital with lumbago about two weeks previously, and headache six days previously. Brain MR imaging revealed no remarkable findings except for left ethmoid sinusitis; both MR angiography and venography showed no vascular abnormalities. On the day after admission, lumbar puncture was performed because right homonymous hemianopsia and nuchal stiffness developed. The cerebrospinal fluid appeared bloody, and the source of bleeding was searched for. MR images of the lumbar spine demonstrated an intradural tumor with heterogenous contrast enhancement, and this tumor was considered to be the source of the bleeding. Tumor resection was performed, but some parts of the tumor could not be resected because of adhesion to the cauda equina. The pathological findings of the tumor demonstrated myxopapillary ependymoma. Radiation therapy was added to treat the residual tumor because myxopapillary ependymoma tended to recur in spite of the benign nature of the tumor. Spinal myxopapillary ependymoma is rare, but it causes subarachnoid hemorrhage. Subarachnoid hemorrhage from spinal tumor should be suspected when headache accompanied with severe low back pain are present even in the absence of spinal signs.

Pigmented neuroendocrine tumor of the lung, showing neuromelanin.

A pigmented neuroendocrine tumor was discovered incidentally in a 62-year-old woman through examination by chest computed tomography. The tumor was located in the left lower lobe, S6, of the lung and was 8 mm in diameter. The preoperative percutaneous needle biopsy was interpreted as a tumor suggestive of small cell carcinoma. Histological examination of the operated lobectomy material revealed that the nodule was a neuroendocrine tumor consisting of mainly spindle-shaped cells and several pigmented cells. Electron microscopy showed several dense-core neurosecretory-type granules in tumor cells, as well as abundant, pleomorphic electron-dense granules in pigmented cells much larger in size and most consistent with lipofuscin or neuromelanin. No melanosomes or premelanosomes were identified. Considering the result of ultrastructural and histochemical studies, the pigment was considered most likely neuromelanin. Neuromelanin is found in neurons of substantia nigra and locus ceruleus, and sympathetic ganglion cells. It is rarely found in neuroendocrine tumors and we review the available reports regarding pigmented carcinoid tumor.

Spontaneous regression of malignant lymphoma of the breast.

A complete spontaneous regression of diffuse large B cell lymphoma involving the right breast, confirmed by aspiration cytology, is reported. The patient visited a hospital due to the rapid growth of a tumor in the right breast. Five years previously she underwent a craniotomy for a brain tumor, diagnosed as B-cell malignant lymphoma, and received several courses of irradiation to the brain. Analysis of the breast tumor cells obtained by aspiration revealed lymphoma cells morphologically, which were similar to the tumor cells in the brain expressing CD20. While waiting for further examination, the tumor regressed rapidly and was not palpable after 20 days. An excisional biopsy of the breast exhibited no definite malignant lymphoma cells among a diffuse population of CD45RO and CD8-positive small lymphocytes. Nucleotide sequencing of HCDR3s of the brain tumor and breast tumor cells showed a completely matched sequence, revealing the breast mass to be a metastatic lesion from the tumor of the brain. Although there was no tumorous lesion, the patient received additional chemotherapy and has shown no sign of recurrence in the breast for 7 years. We were able to confirm that the breast lymphoma shown in the aspiration cytology was a metastatic one, which was not proven histologically prior to chemotherapy, and regard the present case as a malignant lymphoma of the breast showing spontaneous regression. The present case shows a rare occurrence of spontaneous regression of diffuse large B cell malignant lymphoma after aspiration and suggests that CD8-positive T cells might be related to the regression.