[Adenopathy and mammary carcinoma: It is sometimes in the details that one encounters hypersensitivity pneumonitis!] / Adénopathie et carcinome mammaire : c'est dans les détails que se cache la pneumopathie d'hypersensibilité !

INTRODUCTION: Hypersensitivity pneumonitis (HP) is an interstitial lung disease due to an immunological reaction to exposure, by inhalation, to a large variety of antigens. The patho-physiological mechanism remains poorly understood. The diagnosis can be challenging and requires a detailed medical history taking especially when the clinical presentation is atypical or when the causal agent remains unknown. CASE REPORT: We report the case of a 75-year-old woman with a history of mammary carcinoma who presented with recently identified intramammary adenopathy. Biopsy of the adenopathy revealed non-necrotising, giant cell epithelioid granuloma. A diagnosis of hot tub lung with extra-pulmonary granulomatous lymph node involvement was made based on the clinical, functional, radiological and microbiological investigations. The evolution was favorable following antigen avoidance. CONCLUSION: Extrapulmonary lymph node involvement is rare in HP, suggesting a systemic inflammatory involvement.