The patient, an 88‐year‐old man, presented with a painful right first metatarsal joint—with acute onset of symptoms—persisting for the last 24 hours. He had been hospitalized for cerebral ischemic stroke due to internal carotid artery stenosis for 1 week and had been treated with low‐dose acetylsalicylic acid and clopidogrel. A carotid artery thrombectomy was performed 24 hours prior to onset of arthralgia. The patient had no fever, and his vital parameters (blood pressure, heart rate, oxygen saturation) were normal. He had chronic impaired kidney function, with a creatinine level of 126 μmol/l (normal range: <95 μmol/l). Uric acid levels were elevated at 522 μmol/l (normal range: 150‐360 μmol/l). An ultrasound examination of the first metatarsal joint showed an effusion of the first metatarsal joint and a double contour sign, indicating monosodium urate crystal deposition. We performed ultrasound‐guided arthrocentesis. Examination of synovial fluid with polarizing light microscopy revealed multiple spherulites consisting of an aggregation of strongly negative birefringent crystals (the black arrow in the figure, magnification ×400, indicates the axis of the compensator) and identified as monosodium urate spherulites. There was no evidence of interaction of neutrophils with spherulites. The joint was injected with 10 mg of triamcinolone acetonide, and the start of urate‐lowering therapy was recommended. Fiechtner and Simkin (1) have described urate spherulites in gouty synovia in vivo, and further studies have demonstrated that urate crystals may grow in spherulites in vitro (2, 3). The mechanism of spherical aggregation of urate crystals as spherulites is poorly understood, although large supersaturation and cool temperatures might have an impact in formation of spherulites due to epitaxial nucleation (3). Although polarization microscopy of synovial fluids in patients with gout shows monosodium urate in needle shape in the vast majority of cases, crystallization in vivo can also lead to urate spherulites, which are considered as equally specific for the diagnosis of gout.