From Effusion to Conclusion: Diagnosis of Intrathoracic Kaposi Sarcoma With Video-Assisted Thoracoscopic Surgery

Abstract

Kaposi sarcoma (KS) is an angioproliferative neoplasm driven by human herpesvirus-8 that primarily affects immunocompromised patients, particularly patients with advanced HIV infection or AIDS. Pulmonary and pleural involvement is uncommon and may mimic other infections or malignant diseases. We report a 49-year-old man with AIDS and recurrent pleural effusions in whom repeated thoracenteses were nondiagnostic. Diagnosis was ultimately achieved through video-assisted thoracoscopic surgery, revealing intrapleural lesions consistent with KS on human herpesvirus-8 immunostaining. This case emphasizes the importance of maintaining suspicion for KS in immunocompromised patients with unexplained effusions and underscores the dual diagnostic and therapeutic value of video-assisted thoracoscopic surgery.

Kaposi sarcoma (KS) is a vascular neoplasm first described in 1872 and later identified as being associated with human herpesvirus-8 (HHV-8) infection. The disease manifests in several forms—classic, endemic African, iatrogenic, and AIDS-associated—the last being the most aggressive. Whereas cutaneous lesions are the hallmark presentation, thoracic involvement, including pulmonary and pleural disease, is far less common and often difficult to diagnose because of nonspecific radiographic and clinical findings. Direct chest wall involvement in KS is exceedingly rare. Literature review revealed only isolated reports describing intrapleural KS identified by video-assisted thoracoscopic surgery (VATS).

A 49-year-old man with a history of gastroesophageal reflux disease and AIDS (diagnosed 20 years previously) presented with progressive dyspnea, nonproductive cough, and exertional shortness of breath. His antiretroviral therapy (ART) adherence had been intermittent as a result of lapses in insurance coverage.

On admission, laboratory findings showed leukopenia (white blood cell count, 3.9 ×10⁹/L), microcytic anemia (hemoglobin, 4.3 g/dL), and elevated B-type natriuretic peptide (3391 pg/mL). The result of polymerase chain reaction testing for severe acute respiratory syndrome coronavirus 2 was positive. Chest imaging revealed large bilateral pleural effusions, and the patient was admitted to the intensive care unit for presumed acute decompensated heart failure with concurrent coronavirus disease 2019 (COVID-19).

Immunologic testing revealed an HIV viral load of 687,000 copies/mL and a CD4 count of 31 cells/μL. Physical examination demonstrated purplish raised nodules on the patient’s neck, forehead, and thigh. The result of polymerase chain reaction testing for HHV-8 was positive, but biopsy was deferred during his COVID-19 infection. Results of an extensive infectious disease workup were otherwise negative. Echocardiography showed a mildly reduced ejection fraction (51%-54%). Bilateral thoracenteses drained 1.6 L and 870 mL, respectively; cytologic examination results were negative for malignancy. The patient improved clinically and was discharged on trimethoprim-sulfamethoxazole prophylaxis. ART with bictegravir, emtricitabine, and tenofovir alafenamide (Biktarvy) was initiated 30 days later.

Two months later, the patient presented again, with recurrent dyspnea. Chest radiography again demonstrated bilateral pleural effusions. His CD4 count had improved to 181 cells/μL, and the skin lesions had resolved. Repeat thoracentesis showed exudative effusion (lactate dehydrogenase ratio, 0.7; protein ratio, 0.8) with negative cytologic findings. Given the patient’s recurrent effusions and nondiagnostic workup, he was referred for right-sided VATS.

With the patient under general anesthesia, approximately 2 L of turbid, milky fluid were evacuated. Multiple violaceous lesions were identified along the parietal pleura and anterior chest wall (Figure 1). Biopsy samples were obtained, and talc pleurodesis (8 g) was performed. A 28F chest tube was placed after lung reexpansion.

Figure 1.

Intraoperative images from right-sided video-assisted thoracoscopic surgery demonstrating anterior chest wall and lung lesions that were biopsied and confirmed as Kaposi sarcoma.

Histopathologic examination revealed atypical vascular proliferation and chronic inflammation consistent with KS (Figure 2). Immunohistochemical staining for HHV-8 confirmed the diagnosis (Figure 3). Pleural fluid cytologic findings remained negative. The patient recovered uneventfully and was discharged for oncology follow-up.

Figure 2.

Pleural biopsy showing atypical vascular proliferation with focal extravasation of red blood cells (hematoxylin and eosin; original magnification ×400).

Figure 3.

Human herpesvirus-8 immunostain highlighting nuclei of infected cells (original magnification ×400).

Two months post-VATS, the patient returned with worsening dyspnea. Computed tomographic imaging showed a large left hydropneumothorax, residual pleural effusion, and multiple lytic lesions in the thoracic spine and left humerus. Results of bone marrow biopsy were negative for dysplasia. The hydropneumothorax was managed conservatively with pigtail catheter drainage.

Subsequently, the patient experienced dysphagia and aspiration pneumonia. Endoscopy revealed severe esophageal stenosis with ulcerated mucosa. Biopsy confirmed ulceration and inflammation without malignancy. Given the progression of disseminated KS, he began systemic chemotherapy with liposomal doxorubicin (20 mg/m²) and granulocyte colony-stimulating factor support. After 3 cycles, he reported improved respiratory symptoms, and follow-up computed tomography demonstrated decreased effusions and pulmonary consolidation.

Comment

KS is an angioproliferative neoplasm caused by HHV-8 infection and is the most common AIDS-associated malignant disease. Among its 4 recognized variants—classic, endemic African, iatrogenic, and AIDS-associated—the last is most aggressive.^1,2 Up to 90% of KS cases initially manifest with cutaneous lesions before progressing to visceral involvement. Pulmonary KS occurs in approximately 5% of patients and poses significant diagnostic difficulty given the overlap with infections such as Pneumocystis jirovecii pneumonia or tuberculosis.^1,2

Although highly active ART has dramatically reduced KS incidence, the risk in HIV-positive individuals remains more than 30-fold higher than in the general population.^3,4 KS can develop or worsen soon after ART initiation as part of the immune reconstitution inflammatory syndrome.5, 6, 7 This typically arises within 6 months of starting therapy and may manifest as progression of preexisting or occult disease.⁷ In our patient, clinical deterioration with recurrent effusions and skeletal involvement occurred shortly after ART initiation, findings consistent with KS immune reconstitution inflammatory syndrome.

Diagnosis of thoracic KS relies on a combination of radiographic, cytologic, and histopathologic findings. Bronchoscopic biopsy is often limited by submucosal lesion location and a high risk of bleeding or pneumothorax, with diagnostic yield reported in only 45% of 73% of cases.⁸ Pleural fluid cytologic examination is rarely diagnostic. In such cases, VATS offers a minimally invasive means to obtain adequate tissue for histopathologic and immunohistochemical analysis while simultaneously allowing for therapeutic pleurodesis.

Our case demonstrates that VATS can play a crucial diagnostic role. The presence of pleural and chest wall lesions was unexpected because direct chest wall involvement in KS is exceedingly rare. Literature review revealed only isolated reports describing intrapleural KS identified by thoracoscopy. The ability to visualize and sample lesions under direct vision allowed definitive diagnosis in this patient, thereby avoiding delay from repeated nondiagnostic thoracenteses.

Treatment of disseminated KS centers on combination ART to restore immune function, with systemic chemotherapy reserved for visceral or progressive disease. Liposomal anthracyclines such as doxorubicin remain first-line agents for AIDS-associated KS. In our patient, systemic therapy produced both clinical and radiologic improvement.6, 7, 8

This case underscores several key points: (1) negative cytologic findings do not exclude KS in immunocompromised patients with recurrent effusions; (2) VATS can simultaneously provide therapeutic pleurodesis and obtain diagnostic-quality tissue; and (3) intrathoracic and chest wall KS, although rare, should be considered in patients with advanced HIV and unexplained pleural disease. Notably, a diagnosis of KS involving the chest wall in VATS is exceedingly rare, with very limited comparable cases in the current literature.