Urothelial Carcinoma of the Bladder With Primary Metastasis to the Brain: A Case Report and Literature Review.

Brain metastases are the most common type of brain tumor in adults, commonly arising from primary tumor sites of the lung, breast, skin (melanoma), colon, and kidney. Isolated central nervous system (CNS) metastasis arising from urothelial carcinoma (UC) is a rare presentation yielding a poor prognosis. A 71-year-old male patient with a history of urothelial carcinoma, treated one year prior with partial cystectomy and adjuvant gemcitabine and cisplatin (GC) therapy, presented with worsening neurological symptoms, including progressively worsening dizziness, shuffling gait, drifting, expressive aphasia, and confusion. MRI revealed a left frontal 4.0 x 3.6 cm brightly contrast-enhancing tumor with possible hemorrhage, extensive vasogenic edema, and moderate mass effect. An additional smaller right cerebellar lesion was also noted. Outpatient CT of his chest, abdomen, and pelvis revealed no evidence of other malignant sites. He ultimately underwent a left craniotomy with a total resection of his left frontal mass. Pathological examination revealed a urothelial primary. Post-operative MRI revealed complete resection of the left frontal mass and the patient was discharged with no neurologic deficits on exam. In many cases, brain metastases may present years later following initial therapy of UC as the CNS may act as a sanctuary site during systemic chemotherapy. Chemotherapeutics such as gemcitabine with better penetration of the blood-brain barrier may be beneficial in delaying the onset of these metastases.

Ultradoping Boron on Si(100) via Solvothermal Chemistry*.

Ultradoping introduces unprecedented dopant levels into Si, which transforms its electronic behavior and enables its use as a next-generation electronic material. Commercialization of ultradoping is currently limited by gas-phase ultra-high vacuum requirements. Solvothermal chemistry is amenable to scale-up. However, an integral part of ultradoping is a direct chemical bond between dopants and Si, and solvothermal dopant-Si surface reactions are not well-developed. This work provides the first quantified demonstration of achieving ultradoping concentrations of boron (∼1e14 cm2 ) by using a solvothermal process. Surface characterizations indicate the catalyst cross-reacted, which led to multiple surface products and caused ambiguity in experimental confirmation of direct surface attachment. Density functional theory computations elucidate that the reaction results in direct B-Si surface bonds. This proof-of-principle work lays groundwork for emerging solvothermal ultradoping processes.