Introduction

Kaposi sarcoma (KS) is a multifocal vascular tumor first described by dermatologist Moritz Kaposi in 1872.¹ It is associated with human herpesvirus 8 (HHV-8) and typically affects mucocutaneous sites and skin of the lower extremities and face.² KS is classified into 4 clinical forms: (1) classic, (2) endemic, (3) AIDS related, and (4) iatrogenic or transplant related.³ Classic KS (CKS) predominantly affects immunocompetent elderly men of Mediterranean, East European, or Jewish origin, typically causing cutaneous lesions.² Although all forms of KS have been reported in atypical anatomic locations in patients with HIV,² primary CKS in the parotid gland without cutaneous involvement in an HIV-negative patient is exceptionally rare.^4,5 To date and to our knowledge, only a handful of such cases have been reported.⁵ We present a rare occurrence of primary CKS in the parotid gland of an HIV-negative patient.

Report of a Case

A White man in his 60s of Mediterranean (Italian) origin with a medical history notable for hypertension, Hashimoto thyroiditis, nephrolithiasis, and gout presented with an 8-month history of a lump on his right face. He had previously tested positive for COVID-19 infection in November 2021 and was treated with monoclonal antibodies. In February 2022, he developed a painful lump on the right side of his face. A computed tomographic (CT) scan of the neck in August 2022 revealed a 2.3-cm enhancing mass in the right parotid gland as shown in Figure 1. An ultrasound-guided biopsy confirmed histopathologic findings consistent with KS. HIV infection was ruled out and all other laboratory blood test results were unremarkable. No cutaneous lesions were identified. The patient underwent a planned right superficial parotidectomy with no complications. Final pathologic findings confirmed KS arising in the intraparotid lymph node with a strong nuclear staining for HHV-8 immunohistochemical analysis as shown in Figure 2. The patient exhibited intact facial nerve function and was discharged on postoperative day 3. At the 6-month follow-up, he showed a well-healed incision with no signs of recurrence.

Figure 1.  Computed Tomographic (CT) Images

A, Axial view on CT scan of the neck. B, Coronal view of the parotid mass on CT of the neck. The arrowheads indicate a 2.3-mm mass in the right parotid gland. 3D indicates 3 dimensional.

Figure 2.  Histopathologic Images

A, Low-power view shows a well-circumscribed nodule composed of intersecting fascicles of spindle cells, arising within a periparotid lymph node, evidenced by a rim of residual lymphoid tissue and parotid gland parenchyma (hematoxylin-eosin stain). B, High-power view of the tumor shows intersecting fascicles of uniform spindle cells with mild cytologic atypia, and numerous slitlike spaces filled with erythrocytes (hematoxylin-eosin stain). C, Palely eosinophilic hyaline globules are characteristic of Kaposi sarcoma and can be intracytoplasmic or extracellular (hematoxylin-eosin stain). D, Tumor cells display strong nuclear staining for human herpesvirus 8 immunohistochemistry.

Discussion

KS is typically associated with men with HIV, presenting as cutaneous lesions on extremities. Head and neck KS is rare, especially within a salivary gland in an HIV-negative patient, with fewer than 10 such cases reported.⁵ We present a case of CKS in an HIV-negative patient’s intraparotid lymph node. The unique location of CKS in this patient with negative HIV test results and no cutaneous involvement makes this an informative case for head and neck surgeons. Clinical suspicion for KS in HIV-negative patients is limited due to the rarity of HHV-8 infection in such patients.² The cause of CKS in this patient remains uncertain. Given this patient is of Italian origin, one possibility is the reactivation of a latent HHV-8 after administration of monoclonal antibodies for COVID-19 treatment. Although immunosuppressive drugs such as prednisolone used for COVID-19 treatment have been linked to the iatrogenic form of KS,⁶ this patient did not receive steroids and was not immunocompromised at diagnosis. Clinicians should elevate their index of suspicion for rare malignant abnormalities like KS in unconventional locations among Mediterranean populations in the setting of new masses or lumps given the relatively higher prevalence of latent HHV-8 infections in these populations.⁶

Conclusions

We present a rare case of KS in the intraparotid lymph node of an HIV-negative patient, discovered after painful facial swelling following months after COVID-19 treatment with monoclonal antibodies. The patient successfully underwent right superficial parotidectomy with no signs of recurrence at the 6-month follow-up. Clinicians should be vigilant for KS in unusual locations, even in the absence of HIV or immunocompromised status, for patients of Mediterranean origin.