Hypertrophic olivary degeneration (HOD) is a unique form of transneuronal degeneration caused by a disruption of the dentato-rubro-olivary pathway, also known as the triangle of Guillain-Mollaret. The triangle of Guillain-Mollaret is involved in fine voluntary motor control and consists of both the inferior olivary nucleus and the red nucleus on one side and the contralateral dentate nucleus. Clinically, patients classically present with symptomatic palatal myoclonus. Typical magnetic resonance imaging findings include T2-hyperintensity and enlargement of the inferior olivary nucleus evolving over time to atrophy with residual T2-hyperintensity. In this article, we provide a case-based illustration of the anatomy of the Guillain-Mollaret-triangle and the typical imaging findings of hypertrophic olivary degeneration.
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Granular cell tumors are rare soft tissue tumors that may occur in the breast. While almost always benign, they may mimic a malignant tumor both clinically and on imaging.
Automated breast ultrasound is a three-dimensional ultrasonographic technique allowing the evaluation of women with dense glandular breast tissue. In this group of patients, mammography has a low sensitivity because dense breasts can obscure breast cancer on mammogram. On the other hand, women with dense breast tissue, types C and D on the BI-RADS scale, are at an increased risk of developing breast cancer compared to women with fatty breast tissue. Automated breast ultrasound is a standardized and reproducible ultrasound technique which improves breast cancer detection and is promising in the screening and diagnostic settings: it increases the detection of breast cancer, and helps to differentiate benign and malignant lesions. Unfortunately, automated breast ultrasound also has its limitations and disadvantages due to artifacts caused by poor positioning, and lesion and patient characteristics. Many artifacts can be avoided by training and experience of the performing technician. Furthermore, familiarity of the interpreting breast radiologist with these artifacts and pitfalls will decrease false negative diagnosis of true lesions.
Teaching point: Idiopathic granulomatous mastitis is a rare disease that may present as breast abscesses and may mimic other inflammatory, infectious, or neoplastic disorders on imaging.
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