Disseminated mycobacterium avium complex spinal osteomyelitis in a patient with interferon gamma receptor deficiency: A case report.

Disseminated mycobacterium avium complex (MAC) infection is rare and is classically associated with immunodeficient states. Osteomyelitis is a rare manifestation of disseminated MAC infection. The overwhelming majority of MAC infections occur in patients with human immunodeficiency virus (HIV). Disseminated MAC infection has been described in interferon gamma receptor deficiency, an immunodeficiency mechanistically linked to mycobacterial infection. We present a case of disseminated MAC vertebral osteomyelitis in a patient with interferon gamma receptor deficiency.

Primary adrenal leiomyosarcoma.

Primary adrenal leiomyosarcoma is a very rare mesenchymal tumor that arises from smooth muscle cells in the wall of the central adrenal vein or its branches (1). Less than 50 cases have been published in the English literature (2). The tumors are aggressive and often metastasize. This report describes a case of primary adrenal leiomyosarcoma that presented as intermittent left flank pain of 6 months duration in an otherwise healthy 58-year-old Caucasian female. The patient was initially imaged with an abdominal ultrasound, which revealed a left suprarenal mass. A follow-up CT of the abdomen and pelvis confirmed a malignant appearing left adrenal mass. A subsequent PET-CT demonstrated increased metabolic activity within the adrenal mass without evidence of metastasis. Biopsy proven metastasis eventually was detected on surveillance CT studies over the course of 2.5 years. Since this is such a rare malignancy, documenting its imaging findings with multiple modalities is of importance to add to the medical literature and help further characterize its imaging features.

Herpes simplex virus-1 encephalitis secondary to whole brain radiation therapy for metastatic renal cell carcinoma.

Herpes simplex virus-1 (HSV-1) infection is the most common cause of encephalitis. This virus commonly lays dormant in neural ganglia, specifically the trigeminal ganglia, following retrograde axonal transport from the site of infection. States of immunosuppression can activate the virus to cause active infection. There are several causes of immunosuppression that can cause viral reactivation. Sporadic case reports have demonstrated HSV-1 encephalitis following brain radiotherapy, although no clear relationship between this treatment and HSV-1 encephalitis has been elucidated. HSV1 encephalitis that arises during immunocompromized states has an atypical presentation for encephalitis, potentially obfuscating the diagnosis and delaying subsequent treatment. The main diagnostic criteria, including CSF analysis, brain imaging, and clinical presentation, all commonly present atypically during states of immunosuppression. For these reasons, it is imperative for physicians to be aware of this rare sequelae in appropriate populations, such as patients undergoing brain radiotherapy. We present a case of an atypical presentation of HSV-1 encephalitis in a patient who recently completed radiotherapy for brain metastases secondary to renal cell carcinoma.

Bilateral common iliac vein stent migration.

Venous stent migration to the heart is considered to be a rare complication of a common procedure. Therefore, many physicians do not include this complication in their differential diagnosis. We explain why this complication is likely more common than currently thought and why it should be considered as a potential diagnosis. This case describes migration of bilateral iliac vein stents into the right ventricular outflow tract and right interlobar pulmonary artery. We provide multiple imaging modalities demonstrating the migrated stents. We believe radiologists should be cognizant of this complication and consider it as a potential diagnosis. Hopefully, this will create a greater awareness of this life-threatening complication of venous stent placement.

ABCE1 Regulates RNase L-Induced Autophagy during Viral Infections.

Host response to a viral infection includes the production of type I interferon (IFN) and the induction of interferon-stimulated genes that have broad antiviral effects. One of the key antiviral effectors is the IFN-inducible oligoadenylate synthetase/ribonuclease L (OAS/RNase L) pathway, which is activated by double-stranded RNA to synthesize unique oligoadenylates, 2-5A, to activate RNase L. RNase L exerts an antiviral effect by cleaving diverse RNA substrates, limiting viral replication; many viruses have evolved mechanisms to counteract the OAS/RNase L pathway. Here, we show that the ATP-binding cassette E1 (ABCE1) transporter, identified as an inhibitor of RNase L, regulates RNase L activity and RNase L-induced autophagy during viral infections. ABCE1 knockdown cells show increased RNase L activity when activated by 2-5A. Compared to parental cells, the autophagy-inducing activity of RNase L in ABCE1-depleted cells is enhanced with early onset. RNase L activation in ABCE1-depleted cells inhibits cellular proliferation and sensitizes cells to apoptosis. Increased activity of caspase-3 causes premature cleavage of autophagy protein, Beclin-1, promoting a switch from autophagy to apoptosis. ABCE1 regulates autophagy during EMCV infection, and enhanced autophagy in ABCE1 knockdown cells promotes EMCV replication. We identify ABCE1 as a host protein that inhibits the OAS/RNase L pathway by regulating RNase L activity, potentially affecting antiviral effects.