Validation of the updated Bosniak classification (2019) in pathologically confirmed CT-categorised cysts.

INTRODUCTION: The updated Bosniak classification in 2019 (v2019) addresses vague imaging terms and revises the criteria with the intent to categorise a higher proportion of cysts in lower-risk groups and reduce benign cyst resections. The aim of the present study was to compare the diagnostic accuracy and inter-observer agreement rate of the original (v2005) and updated classifications (v2019). METHOD: Resected/biopsied cysts were categorised according to Bosniak classifications (v2005 and v2019) and the diagnostic accuracy was assessed with reference to histopathological analysis. The inter-observer agreement of v2005 and v2019 was determined. RESULTS: The malignancy rate of the cohort was 83.6% (51/61). Using v2019, a higher proportion of malignant cysts were categorised as Bosniak ≥ III (88.2% vs 84.3%) and a significantly higher percentage were categorised as Bosniak IV (68.9% vs 47.1%; p = 0.049) in comparison to v2005. v2019 would have resulted in less benign cyst resections (13.5% vs 15.7%). Calcified versus non-calcified cysts had lower rates of malignancy (57.1% vs 91.5%; RR,0.62; p = 0.002). The inter-observer agreement of v2005 was higher than that of v2019 (kappa, 0.70 vs kappa, 0.43). DISCUSSION: The updated classification improves the categorisation of malignant cysts and reduces benign cyst resection. The low inter-observer agreement remains a challenge to the updated classification system.

Wave Packet Dynamics in Synthetic Non-Abelian Gauge Fields.

It is generally admitted that in quantum mechanics, the electromagnetic potentials have physical interpretations otherwise absent in classical physics as illustrated by the Aharonov-Bohm effect. In 1984, Berry interpreted this effect as a geometrical phase factor. The same year, Wilczek and Zee generalized the concept of Berry phases to degenerate levels and showed that a non-Abelian gauge field arises in these systems. In sharp contrast with the Abelian case, spatially uniform non-Abelian gauge fields can induce particle noninertial motion. We explore this intriguing phenomenon with a degenerated Fermionic atomic gas subject to a two-dimensional synthetic SU(2) non-Abelian gauge field. We reveal the spin Hall nature of the noninertial dynamic as well as its anisotropy in amplitude and frequency due to the spin texture of the system. We finally draw the similarities and differences of the observed wave packet dynamic and the celebrated Zitterbewegung effect of the relativistic Dirac equation.

Teratoma involving adrenal gland - A case report and review of literature.

Teratomas are germ cell tumors which are mainly gonadal in origin. Other common extra-gonadal sites are mediastinal, sacro-coccygeal and pineal regions. Adrenal teratomas are extremely rare and primary adrenal teratomas are even rarer. We reported a case of primary adrenal teratoma in a 60-year-old male. We reviewed literature from 2000 to till date, and found 29 adult cases and 6 paediatric cases of adrenal teratoma. Usually, they are asymptomatic and identified as an incidental finding. Imaging modality such as USG, CT and MRI are useful in diagnosis. Though these tumors are mostly benign, malignant transformation may occur. Treatment includes surgical removal.

Primary spinal primitive neuroectodermal tumor on MR imaging.

Neoplasms in the region of filum terminale are not uncommon. Myxopapillary ependymoma is the commonest tumor at this location. The differentials reported for this entity are nerve sheath tumor, meningioma, paraganglioma, intradural metastases, lymphoma, other varieties of ependymoma, subependymoma, astrocytoma, ganglioglioma, hemangioblastoma, and primitive neuroectodermal tumor (PNET). PNET may very rarely present as an intradural thoracolumbar mass. We present pre- and post-therapy magnetic resonance imaging (MRI) features of a patient with proven primary spinal primitive neuroectodermal tumor (PSPNET) of peripheral subtype.

Retroperitoneal Cystic Malignant Fibrous Histiocytoma Mimicking a Psoas Abscess.

Primary neoplasms in the psoas muscle including schwannoma and soft tissue sarcoma with secondary cystic degeneration are rare entities. They are difficult to distinguish from psoas abscess purely based on radiological findings. Malignant fibrous histiocytoma (MFH) in the retroperitoneum is an uncommon entity in contrast to liposarcoma and leiomyosarcoma. Psoas abscess is a common infection in the retroperitoneum, especially in regions where tuberculosis is endemic. In the current case, the patient presented with gradually progressive lower abdominal pain and raised erythrocyte sedimentation rate (ESR), lymphocyte count and sputum positive for acid fast bacilli. There was a presence of previous history of skeletal tuberculosis. Imaging revealed well-defined multilocular cystic lesion involving the left psoas muscle which along with the clinical scenario suggested psoas abscess. However, post-operative biopsy showed the lesion to be a MFH with extensive cystic degeneration. To the best of our knowledge, cystic MFH mimicking an abscess has been previously reported only once in an oncology literature.