Faculty Bibliography

Renal mucinous tubular and spindle cell carcinoma (MTSCC) was recently described as a distinct subtype of renal cell carcinoma (RCC) in the 2004 World Health Organization classification of kidney tumors. MTSCC is a rare low grade malignancy with < 100 cases reported in the literature. To the best of our knowledge, there are 5 case reports with a total of 6 patients describing its diagnosis by fine needle aspiration (FNA). All of these cases were diagnosed as conventional RCC on FNA. Subsequent excisions proved them to be MTSCC. We herein report a case in a 67-year-old male. He presented with abdominal pain and was found to have a new colon adenocarcinoma with metastasis to the liver and lungs. The extent of disease made the patient ineligible for surgical excision, and he received chemotherapy. Work-up also revealed a kidney mass which was later biopsied by FNA and core biopsy. The tumor was composed of epithelial and spindled cell components embedded in a myxoid background. It was positive for CK7, AMCAR, vimentin, and epithelial membrane antigen. The tumor was diagnosed as MTSCC. One year later the kidney mass remained stable. However, the patient developed new metastasis to the liver from colonic primary. The kidney mass was not resected. Although rarely encountered in FNA cytology of the kidney, we believe the cytologic features of this tumor are distinctive and are different from conventional and other subtypes of RCC. Therefore, its accurate diagnosis on FNA is possible once pathologists are aware that MTSCC should be considered in the differential diagnosis of kidney tumors.

BACKGROUND: The electrocardiogram (ECG) is the most important diagnostic tool for acute myocardial infarction (AMI). T wave inversion (TWI) in lead aVL has not been emphasized or well recognized. OBJECTIVE: This study examined the relationship between the presence of TWI before the event and mid-segment left anterior descending (MLAD) artery lesion in patients with AMI. METHODS: Retrospective charts of patients with acute coronary syndrome between the months of January 2009 and December 2011 were reviewed. All patients with MLAD lesion were identified and their ECG reviewed for TWI in lead aVL. RESULTS: Coronary angiography was done on 431 patients. Of these, 125 (29%) had an MLAD lesion. One hundred and six patients (84.8%) had a lesion > 50% and 19 patients (15.2%) had a lesion < 50%. Of the 106 patients who had a MLAD lesion > 50%, 90 patients (84.9%) had TWI in lead aVL and one additional lead. Of the 19 patients who had an MLAD lesion < 50%, 8 patients (42.1%) had TWI in lead aVL and one additional lead. Isolated TWI in lead aVL had an overall sensitivity of 76.7% (95% confidence interval [CI] 0.65-0.86), a specificity of 71.4% (95% CI 0.45-0.88), a positive predictive value of 92%, a negative predictive value of 41.7%, a positive likelihood ratio of 2.7 (95% CI 1.16-6.22), and negative likelihood ratio of 0.32 (95% CI 0.19-0.58) for predicting a MLAD lesion of > 50% (p = 0.0011). CONCLUSIONS: TWI in lead aVL might signify a mid-segment LAD lesion. Recognition of this finding and early appropriate referral to a cardiologist might be beneficial. Additional studies are needed to validate this finding.

Subthreshold-activating A-type K(+) currents are essential for the proper functioning of the brain, where they act to delay excitation and regulate firing frequency. In CA1 hippocampal pyramidal neuron dendrites, the density of A-type K(+) current increases with distance from the soma, playing an important role in synaptic integration and plasticity. The mechanism underlying this gradient has, however, remained elusive. Here, dendritic recordings from mice lacking the Kv4 transmembrane auxiliary subunit DPP6 revealed that this protein is critical for generating the A-current gradient. Loss of DPP6 led to a decrease in A-type current, specifically in distal dendrites. Decreased current density was accompanied by a depolarizing shift in the voltage dependence of channel activation. Together these changes resulted in hyperexcitable dendrites with enhanced dendritic AP back-propagation, calcium electrogenesis, and induction of synaptic long-term potentiation. Despite enhanced dendritic excitability, firing behavior evoked by somatic current injection was mainly unaffected in DPP6-KO recordings, indicating compartmentalized regulation of neuronal excitability.

Endobronchial ultrasonography (EBUS) has emerged as a new diagnostic tool that allows the bronchoscopist to see beyond the airway, including pulmonary and mediastinal lesion. The real time EBUS-guided transbronchial needle aspiration (TBNA) has advanced the diagnostic yield in primary lung pathology and mediastinal lymph node staging of lung carcinoma. Sixty-four patients (36 males, 28 females, ages ranging from 16 to 86 years) with peribronchial lung lesions and mediastinal and/or hilar lymph node lesions underwent EBUS-TBNA. All patients had intraoperative cytological assessment by smears on aspiration samples or touch preparation on needle core biopsies.The cytological final diagnoses were categorized as negative, suspicious/positive, and non-diagnostic. Forty-nine samples were obtained from lymph node lesions and 15 samples were obtained from lung lesions. In cytology specimens, 32 patients had suspicious/positive diagnoses and 32 patients had negative diagnosis. In follow-up histology specimens, 35 patients had malignant diagnoses, including 18 adenocarcinomas, 8 small cell carcinomas, 6 squamous cell carcinomas, 1 metastatic hepatocellular carcinoma, 1 metastatic melanoma, and 1 lymphoma. Twenty-nine patients had negative diagnoses. Sensitivity and specificity were 88.9% and 96.4%, respectively. Positive and negative predictive values were 97.0% and 87.1%, respectively. Diagnostic accuracy was 92.2%. EBUS-TBNA is an efficient and effective technique for diagnosis of intrapulmonary and mediastinal/hilar lymph nodes. It becomes significantly invaluable on clinical management for staging in those patients with lung cancer of other metastatic malignancies. This technique enables us to obtain tissue samples for quick diagnoses beyond central airway with minimal complications. Diagn. Cytopathol. 2010. (c) 2009 Wiley-Liss, Inc