Episode summary: Case reports sit at the bottom of medicine's evidence hierarchy, yet they account for 12% of all PubMed publications. This episode explores why physicians write them (academic currency, naming rights, journal economics) and how humble observations have sparked FDA-approved treatments — from hydroxychloroquine for porphyria to esketamine for depression. We examine the tension between "interestingness" and importance, the role of post-marketing surveillance, and whether the system generates too much noise. Show Notes Case reports are the most abundant yet least respected publication type in medicine. A single physician writing up one patient's unusual presentation sits at the bottom of the evidence hierarchy, far below randomized controlled trials and meta-analyses. Yet these humble observations account for about 12% of all PubMed-indexed publications, and they serve functions that larger trials cannot. The incentives for writing case reports are entirely non-financial. Medical students and residents need scholarly activity for residency applications and promotions — 68% of U.S. medical students have authored at least one case report by graduation. The "first to describe" prize offers naming rights (Stevens-Johnson syndrome, Hashimoto's thyroiditis). Journals benefit from cheap content that drives citation counts. And case reports fill a critical gap in negative data: failed treatments and adverse events that clinical trials rarely publish. But do they actually change medicine? Yes. A 1987 case report of a porphyria patient improving on hydroxychloroquine took 27 years to become an FDA-approved indication. A 1996 case series of three Kaposi sarcoma patients on HIV protease inhibitors changed cancer treatment paradigms. A 2022 case report of ketamine for treatment-resistant depression helped catalyze the esketamine approval. The FDA's adverse event reporting system, which received over 2 million reports in 2023 alone, is essentially a massive collection of mini case reports — the primary mechanism for detecting rare drug reactions that trials miss. Listen online: https://myweirdprompts.com/episode/case-reports-medical-evidence