Submandibular nodal involvement as the initial presentation of HIV-negative Kaposi sarcoma: a case report

Background. Kaposi sarcoma (KS) is an angioproliferative malignancy driven by human herpesvirus 8 (HHV-8) that most often manifests as cutaneous lesions. Nodal involvement in HIV-negative, immunocompetent individuals, especially as an initial presentation, is exceedingly rare. Head and neck KS accounts for less than 5% of non-AIDS-associated cases, with cervical lymphadenopathy representing only 4.4% of lesion distributions in this population. Case presentation. A 71-year-old HIV-negative Italian man presented with a painless, progressively enlarging submandibular lymphadenopathy. Surgical excision followed by histopathology and immunohistochemistry confirmed nodal KS. Subsequent full-body skin examination identified a previously unrecognized violaceous lesion on the hallux, which was histopathologically confirmed as KS. Conclusions. This case highlights the diagnostic challenges posed by atypical KS presentations and emphasizes the need to include KS in the differential diagnosis of unexplained cervical lymphadenopathy, even in immunocompetent patients without clinically evident cutaneous lesions. Comprehensive dermatologic screening and long-term multidisciplinary surveillance are advised to detect and manage potential disease progression.