A healthy 45-year-old Filipino male initially presented to the emergency department with flu-like symptoms and cough. He also endorsed rare chest burning after heavy meals which was managed with over-the-counter antacids as needed. Prior to these symptoms, the patient had excellent exertional capacity such as playing sports with his children and running and climbing multiple flights of stairs without respiratory ailment.
A history relevant for gastroesophageal reflux disease was recorded. Otherwise, the patient denied any chronic lung conditions such as asthma, recurrent respiratory infections, or pneumonia. No outstanding surgical history. Travel history was unremarkable.
He did transiently smoke cigarettes for 9 months, approximately half a pack a day when he was in his early 20s. He works as an administrator for an office space that renders him at his desk most of the day. He denied exposure to fumes, gas chemicals, or hard metals. He is a Veteran and served in the Gulf War for 7 months. Thereafter, he spent another 8 months in Iraq working in a dusty warehouse for out-processing mail. He never owned any pets. He denied sleeping on or using down material.
Vital signs were stable on initial presentation: afebrile, resting pulse oximetry of 99% with heart rate of 77 beats per minute, blood pressure of 133/76 mm of mercury. Body mass index was noted to be 26. His lungs were clear to auscultation without any wheeze or crackles. All other physical exam findings were normal.
Complete blood count test results acquired dating back over 5 years showed that the patient never manifested peripheral eosinophilia with the largest count of 90 eosinophils/microL. The rest of serologic studies including fungal serologies were negative. A chest roentgenogram (CXR) at the time revealed prominent reticulonodular opacities at the lung bases without significant volume loss (Fig. 1). Subsequent computed tomography (CT) of the chest demonstrated posterior basilar selective micronodular disease consistent with pulmonary ossification (Fig. 2, Fig. 3). Complete pulmonary function testing (PFT) that was performed also revealed a forced vital capacity of 6.2 L (104%), forced expiratory volume in 1 s of 4.7 L (99%), ratio of 76%, total lung capacity of 99% and a DLCO adjusted for hemoglobin of 76%.
By the time the patient was discharged to our pulmonary clinic, his viral syndrome had resolved. He denied any cough, shortness of breath, fevers, wheezing, decreased urine output, or unintentional weight loss. Given his benign asymptomatic presentation and counseling of the patient, we initially opted to monitor the patient without any initial interventions.
Approximately 1 year later, he manifested mild shortness of breath on exertion. Repeat CT of the chest demonstrated stability without any significant changes. PFTs also remained stable. Thus we offered transbronchial biopsies (TBBx) and video assisted thoracic surgery (VATS) biopsy if TBBx was inconclusive.
Eight TBBx were taken in the right lower lobe in 4 different sub-subsegments. Pathology reported evidence of bronchial mucosa and lung parenchyma with focal interstitial fibrosis and multiple foci with dense fibrosis and calcifications, resembling osseous metaplasia. Though suggestive, ultimately non-diagnostic for PO. VATS wedge biopsies were shortly thereafter performed in the right lower lobe, right middle lobe and right upper lobe. Pathology was consistent with multifocal lobulated bone nodules with alveolar spaces with focal bone marrow consistent with dendriform pulmonary ossification (Fig. 4).