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Objective: To perform a retrospective, multicenter, external validation of the Cleveland Clinic malignancy probability prediction model for incidental pulmonary nodules. Patients and Methods: From July 1, 2022, to May 31, 2023, we identified 296 patients who underwent tissue acquisition at Mayo Clinic (MC) (n=198) and Loyola University Medical Center (n=98) with histopathology indicating malignant (n=195) or benign (n=101). Data was collected at initial radiographic identification (point 1) and at the time of intervention (point 2). Point 3 represented the most recent data. The areas under the receiver operating characteristics were calculated for each model per time point. Calibration was evaluated by comparing the predicted and observed rates of malignancy. Results: The areas under the receiver operating characteristics at time points 1, 2, and 3 for the MC model were 0.67 (95% CI, 0.61-0.74), 0.67 (95% CI, 0.58-0.77), and 0.70 (95% CI, 0.63-0.76), respectively. The Cleveland Clinic model (CCM) was 0.68 (95% CI, 0.61-0.74), 0.75 (95% CI, 0.65-0.84), and 0.72 (95% CI, 0.66-0.78), respectively. The mean ± SD estimated probability for malignant pulmonary nodules (PNs) at time points 1, 2, and 3 for the CCM was 64.2±25.9, 65.8±24.0, and 64.7±24.4, which resembled the overall proportion of malignant PNs (66%). The mean estimated probability of malignancy for the MC model at each time point was 38.3±27.4, 36.2±24.4, and 42.1±27.3, substantially lower than the observed proportion of malignancies. Conclusion: The CCM found discrimination similar to its internal validation and good calibration. The CCM can be used to augment clinical and shared decision-making when evaluating high-risk PNs.
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Pulmonary artery pseudoaneurysms (PAPs) are rare and life-threatening occurrences. We present a 57-year-old male patient with squamous cell lung cancer, who presented with hemoptysis. Bronchoscopy did not reveal ongoing bleeding. Imaging showed a left lower lobe tumor, a cavitary lesion communicating with the bronchus, and a pulmonary artery pseudoaneurysm. Successful embolization of the originating segmental branch of the pulmonary artery was performed. The pathogenesis of PAPs associated with primary lung malignancies remains poorly understood. We propose a four-step mechanism involving primary tumor expansion, central cavitary necrosis, direct arterial invasion, inflammatory response, vessel wall damage, pseudoaneurysm formation, and subsequent filling of the former cavitary lesion. This case emphasizes the importance of considering PAPs in primary lung malignancies, particularly in male patients with squamous cell pathology. Understanding the proposed pathogenic mechanism could lead to early detection, prompt intervention, and improved outcomes.
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Histoplasmosis is one of the most common endemic mycoses affecting immunocompromised individuals in the United States and Latin America. Involvement of the central nervous system carries higher mortality rates and worse prognosis, given its resemblance to stroke, vasculitis, and meningitis of other etiologies. The diagnosis is challenging, due to its subtle clinical presentation and the poor sensitivity of the cerebrospinal fluid culture. Herein the authors present a case of a middle-aged man with HIV, who presented with intermittent headaches exacerbated by an oculomotor nerve palsy, concerning for acute stroke. A diagnosis of central nervous system histoplasmosis was made, and his neurological deficits subsided after initiation of treatment. The stroke-like syndrome in this scenario may be secondary to granulomatous vasculitis of small caliber cerebral blood vessels. Histoplasmosis of the central nervous system remains a challenging diagnosis, which requires a high index of suspicion by the clinician for an early institution of therapy in order to improve outcomes.