CHEST Guidelines-A-79-Year-Old-Man-With-Progressive-Dyspnea-and-Mul

A-79-Year-Old-Man-With-Progressive-Dyspnea-and-Mul

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A 79-year-old man with progressive breathlessness and multiple pulmonary nodules presented with a history of type 2 diabetes and prostatic hyperplasia without significant smoking history. Despite intensive testing, including bronchoscopy and whole-body imaging, no definitive diagnosis was established. Lab results showed elevated tumor markers, yet no conventional adenocarcinoma was diagnosed. <br /><br />High-resolution CT scans revealed clustered nodules with interstitial shadows, and 18F-fluorodeoxyglucose (FDG)-PET/CT scanning showed diffuse uptake in the lungs but no significant uptake elsewhere. The patient's condition deteriorated rapidly, with his CT scans showing progressive enlargement and coalescence of nodules. Despite treatment with antibiotics and corticosteroids targeting possible interstitial lung disease exacerbation, the patient's respiratory failure worsened, leading to his death after 40 days.<br /><br />The autopsy revealed diffuse lepidic growth of cancer cells in the lungs and mucus accumulation mimicking invasive mucinous adenocarcinoma. Surprisingly, no primary tumor was evident in traditional sites, except for small and clinically undetectable pancreatic lesions. Extensive lymphatic and nodal invasion was noted. The final diagnosis was diffuse pulmonary metastasis of occult pancreatic carcinoma.<br /><br />This case underscores the challenges of diagnosing metastatic cancer with an occult primary site. It highlights the limitations of imaging like FDG-PET in detecting small or early-stage lymph node metastases. The findings suggest that pancreatic carcinoma should be considered in the differential diagnosis of pulmonary nodules, even when the primary lesion is absent. This case is notable as the first documented instance where occult pancreatic carcinoma resulted in distant metastasis without a discernable primary lesion.

Keywords

occult pancreatic carcinoma

pulmonary nodules

metastatic cancer

lepidic growth

FDG-PET

mucinous adenocarcinoma

tumor markers

respiratory failure

interstitial lung disease

lymphatic invasion