<h4>Background</h4>Patients with platinum-resistant recurrent high grade serous ovarian carcinoma have poor outcomes and limited treatment options.<h4>Case presentation</h4>We present a case of a 48-year-old woman with platinum-resistant high grade serous ovarian carcinoma harboring the pathogenic <i>TSC2</i> R611Q variant with concomitant single copy loss of <i>TSC2</i> (suggesting biallelic <i>TSC2</i> inactivation) identified in targeted tumor sequencing. The gene discussed is TSC2; the disease is ovarian serous carcinoma.