Background

MOGAD is most commonly seen in children and young adults [1]. Optic neuritis is one of the most common clinical presentation of MOGAD and is usually seen bilaterally [2, 3]. Spinal cord findings in MOGAD include abnormal T2 hyperintensity, centrally located involving both gray and white matter [2]. Dubey et al. [4] described a characteristic MRI finding in MOGAD, which was sagittal T2 hyperintense line surrounded by more hazy T2 hyperintense signal involving the anterior and posterior gray matter horns. The spinal cord presentation of MOGAD may be in the form of: a) longitudinally extensive transverse myelitis (involving three or more vertebral segments) or b) short lesions involving less than two vertebral segments [5, 6]. The involvement of conus medullaris is observed more in MOGAD spectrum more than any other reported demyelinating disorders [4, 6, 7].

The hemorrhagic longitudinally extensive transverse myelitis as a standalone finding without the involvement of brain and optic nerves was not reported in any of the MOGAD spectrum of disorders.

Case presentation

Clinical profile

A 15-year-old female came with complaints of sudden onset paraparesis. Patient had history of urinary retention 8 days before the episode of paraparesis. There was no history of trauma/fever/recent vaccination/hereditary disorders/previous history of similar episodes.

Blood investigations

Routine complete blood counts and cerebrospinal fluid evaluations were normal. Serum myelin oligodendrocyte glycoprotein (MOG) antibodies showed seropositivity, while the neuromyelitis optica antibodies (NMOs) were negative.

MRI findings

MRI was performed within 48 h of the onset of paraparesis, which revealed a long-segment, intramedullary, expansile, heterogeneously enhancing spinal cord lesion extending from T1 vertebral level till conus medullaris. Few foci of blooming were also noted in the spinal cord on gradient sequences (Fig. 1a–f). Brain and orbit MRI evaluation was normal. Although consideration was given for spinal tumors like ependymoma and astrocytoma, the acute presentation of the symptoms made them clinically less likely. A diagnosis of MOGAD-associated hemorrhagic longitudinally extensive transverse myelitis was made.

Fig. 1
figure 1figure 1

a T2 W sagittal image and b FLAIR sagittal image showing a long-segment T2 hyperintense signal (orange arrow) extending till conus medullaris, with few hypointense areas (blue arrows) in between. c Gradient sagittal image showing few areas of blooming within the spinal cord(blue arrows). d I–IV T2 W axial images at T8, T10, T11 and T12 levels, respectively, showing expansile T2 hyperintense spinal cord lesion with few hypointense areas within. e T1 fat-saturated pre-contrast sagittal image. f T1 fat-saturated post-contrast sagittal image showing heterogeneous areas of post-contrast enhancement (white arrows)

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Treatment

The patient was started on IV methylprednisolone 1 g/day for 5 days followed by 5 cycles of plasmapheresis on alternate days.

Follow-up

Four weeks following treatment, the patient gradually improved and regained her ability to walk and follow-up MRI revealed significant decrease in the spinal cord lesion (Fig. 2a–c) suggesting good response to the treatment and establishing the diagnosis of MOGAD-positive hemorrhagic longitudinally extensive transverse myelitis.

Fig. 2
figure 2

Follow-up MRI images after 28 days. a: T2 sagittal image showing significant reduction in the T2 hyperintensities within the spinal cord (green arrows), b: Pre-contrast T1 fat-saturated sagittal image, c: Post-contrast T1 fat-saturated sagittal image showing significantly reduced heterogeneous post-contrast enhancement (black arrow) within the spinal cord as compared to previous MRI

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Conclusions

Hemorrhagic longitudinally extensive transverse myelitis as a standalone finding without any involvement of optic nerves and brain may show MOGAD seropositivity and should be considered as one of the differential diagnosis in cases of acute myelopathy.