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|LETTER TO EDITOR
|Year : 2017 | Volume
| Issue : 1 | Page : 175-176
“Hot-cross bun” and “inverse trident sign' in neurosarcoidosis: An important finding
Kadam Nagpal, Puneet Agarwal
Department of Neurology, Max Superspeciality Hospital, Saket, New Delhi, India
|Date of Web Publication||12-Jan-2017|
Department of Neurology, Max Superspeciality Hospital, Saket, New Delhi
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Nagpal K, Agarwal P. “Hot-cross bun” and “inverse trident sign' in neurosarcoidosis: An important finding. Neurol India 2017;65:175-6
A 48-year-old male patient presented with subacute onset progressive asymmetrical (right > left) pancerebellar syndrome of 4 month duration. There was significant associated weight loss and decreased appetite. However, there was no history of fever, headache, vision impairment, seizures, or any stroke. On examination, the patient was conscious and oriented to time, place, and person. The fundus examination was normal and bilateral gaze-evoked nystagmus was present. Spasticity was present (right > left), and deep tendon reflexes were also brisk on the right side, with a right-sided extensor plantar response. Asymmetrical cerebellar signs such as finger–finger test, finger–nose test, and dysdiadochokinesia were seen, more on the right side. The patient had an ataxic gait but there were no meningeal signs on examination. Routine blood investigations were all normal, apart from elevated erythrocyte sedimentation rate [ESR] (ESR: 85 mm). Serum angiotensin converting enzyme levels (127 U/l) were persistently high, whereas other vasculitis markers and human immunodeficiency virus (HIV) results were negative. Cerebrospinal fluid results including herpes simplex virus (HSV) markers and tuberculosis polymerase chain reaction were performed, which were also normal. Magnetic resonance imaging (MRI) of the brain showed a heterogeneous confluent lesion in the right cerebellar hemisphere and right middle cerebellar peduncle, which was isointense-to-hypointense on T1 weighted, and hyperintense on T2-weighted, fluid-attenuated inversion recovery (FLAIR) and diffusion weighted imaging (DWI) sequences with minimal contrast enhancement [Figure 1]a,[Figure 1]b,[Figure 1]c,[Figure 1]d. MR spectroscopy (multivoxel) was also noncontributory. Subsequently, a whole body fludeoxyglucose positron emission tomography–computed tomography scan was done, which showed hypermetabolic lesions in the mediastinal, internal mammary, cervical, submandibular, supraclavicular, and retroperitoneal lymph nodes with cerebellar involvement suggesting the possibility of lymphoma or sarcoidosis [Figure 2]. Mediastinal lymph node biopsy was done and the results revealed multiple epithelioid cell granulomas with multinucleated giant cells without any necrosis. No atypical or malignant cells were seen. Eventually, a possibility of neurosarcoidosis was considered, and intravenous pulse methylprednisolone was started followed by oral steroids. During the course of the treatment, the patient developed new onset left hemiparesis, skew deviation of eyes and bulbar involvement. Following the development of these signs, a repeat MRI of the brain was done which revealed increase in the size and extent of lesion that now involved bilateral cerebellar peduncles, bilateral cerebellar hemispheres, and the brainstem, resulting in a “hot-cross bun” sign and “inverse trident sign” in the upper and middle pons [Figure 3].
|Figure 1: (a-d) Pretreatment magnetic resonance imaging of the brain axial sections showing a confluent heterogeneous hyperintensity at the right cerebellar hemisphere and right middle cerebellar peduncle on T2-weighted, fluid-attenuated inversion recovery, and diffusion weighted imaging images with minimal enhancement seen in post-contrast images|
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|Figure 2: Whole body fludeoxyglucose positron emission tomography–computed tomography scan showing hypermetabolic lesions in the cerebellum as well as mediastinal, internal mammary, cervical, submandibular, supraclavicular, and retroperitoneal lymph nodes|
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|Figure 3: (a) Magnetic resonance imaging (MRI) of the brain, T2-weighted axial section, showing presence of “hot-cross bun” sign at mid pons with assymetrical hyperintensities in the superior cerebellar peduncle; (b) MRI brain T2-weighted axial section showing the “inverse trident” sign at the level of upper pons|
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“Hot-cross bun” sign has been described in the cerebellar type of multiple system atrophy and spinocerebellar ataxia due to the selective loss of myelinated transverse pontocerebellar fibers and neurons in the pontine raphe with preservation of the pontine tegmentum and corticospinal tracts. Other clinical conditions where the “hot-cross bun” sign is reported include a variant of the Creutzfeld–Jakob disease, secondary Parkinsonism More Details, and cerebrotendinous xanthomatosis. On the other hand, a “trident sign” has been reported in Wilson's disease and central pontine myelinolysis. The plausible mechanism for a “trident sign” is the preferential involvement of transverse pontine fibres. We, indeed, postulate a similar mechanism for the “inverse trident sign” because the involvement of transverse pontine fibres was clearly evident in our patient. A combination of both these signs was described by Jain et al., in progressive multifocal leukoencephalopathy due to human immunodeficiency virus infection. To the best of our knowledge, there is no description of a similar radiological finding in neurosarcoidosis. Therapeutic options in neurosarcoidosis primarily include a high dose and a prolonged course of steroids. However, steroid resistance, persistent disease activity, or severe central nervous system disease often require an early introduction of the immunosuppressive therapy. Cytotoxic agents such as methotrexate, cyclophosphamide, cyclosporine, and anti-tumor necrotic factor agents, such as infliximab, are recommended in refractory disease. Given the reports of treatment failure in up to 40% of cases who are on steroids, a combination therapy (steroids + immunosuppressive agents) is preferable at the time of the initial diagnosis.
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[Figure 1], [Figure 2], [Figure 3]