We report on a 71-year-old patient with a classic, primary Kaposi’s sarcoma of the lymph nodes. He presented with an inguinal lymphadenopathy. An ultrasound examination showed suspicious lesions (oval lymph nodes with a single, round, homogeneous hypoechoic structure with peripheral and diffuse vascularization), yet typical sonomorphological criteria for lymph node metastases of a solid malignant tumor such as melanoma (round lymph nodes with a round hypoechoic area that often contains hyperechoic structures due to necrosis and a peripheral vascularization) were not fully met. Nevertheless, due to the suspicious findings, inguinal lymph nodes were extirpated. Histologically, there were formations of a malignant tumor that led to the diagnosis of a nodal Kaposi’s sarcoma. Skin examinations, HIV testing and imaging procedures presented no pathological findings. A therapy with ipilimumab (3mg/kg every three weeks for four times) was initiated, which resulted in durable tumor control. Sonomorphological patterns for Kaposi’s sarcoma of the lymph nodes are not yet defined. We report on this case to describe the specific sonomorphological structures in our patient as a first step towards establishing sonomorphological criteria for nodal Kaposi’s sarcoma. Furthermore, this is the first case to report on a successful first-line therapy with the immune checkpoint inhibitor ipilimumab in classical Kaposi’s sarcoma.