Overview of established and emerging immunohistochemical biomarkers and their role in correlative studies in MRI.

Clinical practice in radiology and pathology requires professional expertise and many years of training to visually evaluate and interpret abnormal phenotypic features in medical images and tissue sections to generate diagnoses that guide patient management and treatment. Recent advances in digital image analysis methods and machine learning have led to significant interest in extracting additional information from medical and digital whole-slide images in radiology and pathology, respectively. This has led to significant interest and research in radiomics and pathomics to correlate phenotypic features of disease with image analytics in order to identify image-based biomarkers. The expanding role of big data in radiology and pathology parallels the development and role of immunohistochemistry (IHC) in the daily practice of pathology. IHC methods were initially developed to provide additional information to help classify tumors and then transformed into an indispensable tool to guide treatment in many types of cancer. IHC markers are used in daily practice to identify specific types of cells and highlight their distributions in tissues in order to distinguish benign from neoplastic cells, determine tumor origin, subclassify neoplasms, and support and confirm diagnoses. In this regard, radiomics, pathomics, and IHC methods are very similar since they enable the extraction of image-based features to characterize various properties of diseases. Due to the dramatic advancements in recent radiomics research, we provide a brief overview of the role of established and emerging IHC biomarkers in various tumor types that have been correlated with radiologic biomarkers to improve diagnostic accuracy, predict prognosis, guide patient management, and select treatment strategies. Level of Evidence: 5 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2020;51:341-354.

Herpes zoster ophthalmicus caught in the (Tr)act!

To emphasize the utility of contrast enhanced MRI for identifying the extent of disease in herpes zoster ophthalmicus with intracranial extension to help determine proper management. We present a rare case of herpes zoster ophthalmicus (HZ/HZO) with intracranial extension and MRI demonstration of involvement of the trigeminal nerve, the trigeminal nucleus, and the spinal trigeminal nucleus and tract. Herpes zoster is caused by reactivation of varicella zoster virus. Herpes zoster ophthalmicus with involvement of the ophthalmic division of the trigeminal nerve has been estimated to account for 10-20% of the cases (Yawn et al. in Mayo Clin Proc 88:562-570, 2013). While postherpetic neuralgia is the most common complication, HZ/HZO can rarely manifest in a more sinister manner resulting in multi-dermatomal involvement, disseminated disease, cranial arteritis (Walker in Radiology 107:109-110, 1973), cranial nerve paresis (O.d in Clinical Eye and Vision Care 11:75-80, 1999), hemiplegia (Cavaletti in The Italian Journal of Neurological Sciences 11:297-300, 1990), ocular/dysfunction (Kocaoglu in Türk Oftalmoloji Dergisi 48:42-46, 2018), and intracranial extension (Chen in BMC Infectious Diseases 17:213, 2017; Yawn in Mayo Clin Proc. 88:562-570, 2013). Contrast enhanced MRI (CE-MRI) can be of great benefit to elucidate the extent of disease and intracranial involvement for institution of more aggressive management to prevent further complications.

Idiopathic Spontaneous Occurrence of Heterotrophic Occurrence During Pregnancy.

Heterotopic ossification (HO) typically presents in the hip, knee, and elbow joints in the setting of trauma or postsurgical intervention. Less commonly, it may occur secondary to neurologic dysfunction or underlying genetic conditions, but idiopathic HO is rare. Most cases of HO are managed nonoperatively with surgical resection remaining a controversy due to high recurrence rates. We describe a case of idiopathic HO of the shoulder that occurred in the absence of trauma, neurologic dysfunction, or underlying genetic disorder that was treated with surgical excision.