D110-16 A Neck Swelling That Breathed: Malignant Pleural Cutaneous Fistula in a Patient With Lung Adenocarcinoma

Abstract Introduction A pleurocutaneous fistula (PCF) is a rare pathological communication between the pleural space and the subcutaneous tissue most encountered as a complication of thoracic surgery, empyema drainage, trauma, or tuberculosis. Spontaneous PCFs are uncommon with only few cases described in our literature review - most often occurring because of direct tumor invasion or radiation-induced necrosis. We report an unusual case of a malignant PCF presenting as a cystic supraclavicular lesion that moved in synchrony with respiration in a patient with lung adenocarcinoma. Case Description A 40-year-old Filipino female, non-smoker, was diagnosed with lung adenocarcinoma in 2024 after presenting with chronic cough, dyspnea, and weight-loss. Imaging revealed a right upper lung mass and bronchoscopy with biopsy revealed lung adenocarcinoma. She underwent concurrent chemoradiation with Carboplatin and Paclitaxel. A month post-treatment, she developed a cyst-like swelling on the right supraclavicular area approximately 3x3cm, that moved with respiration. The lesion progressively enlarged and spontaneously ruptured, leaving a draining sinus at its location. She then developed worsening cough and dyspnea. Chest CT showed the lung mass extending towards a cutaneous defect in the right supraclavicular area, forming a tract between the pleural space and skin—confirming a PCF. Surgical closure was initially planned but poor wound healing was expected due to malnutrition hence she was managed conservatively with wound care, antibiotics, and continued palliative systemic therapy. Discussion PCFs are uncommon and complex. In normal situations, negative intrapleural pressure inhibits the formation of a PCF but the presence of a pulmonary mass in our patient likely interfered with this. The PCF likely resulted from direct tumor invasion of the chest wall complicated by radiation and chemotherapy-induced tissue necrosis with delayed wound healing from malnutrition. The movement of the lesion with respiration was suggestive of pleural communication. After rupture, the open tract allowed passage of air and secretions from the lung and pleura to the skin surface and vice versa predisposing the patient to secondary infections, chronic cough through mechanical irritation and cough reflex stilmulation from pressure changes in the pleural cavity. Surgical closure is often difficult due to poor tissue integrity and ongoing disease activity. Thus, management is primarily supportive and individualized, focusing on infection control, wound care, and palliation. This case illustrates a rare malignant PCF presenting as a respiration synchronous cystic lesion. Awareness of this rare complication allows for timely diagnosis, prevention of infection, and individualized palliative management. This abstract is funded by: None