Abstract Introduction Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) is a precursor of carcinoid tumors stemming from diffuse proliferation of neuroendocrine cells within bronchiolar epithelium. Typical presentation is seen in non-smoking middle aged women with chronic cough and dyspnea. We present a case of DIPNECH coinciding with pulmonary coccidioidomycosis and mycobacterium avium complex (MAC). Case Report A 73-year-old female with asthma, non-smoker presented with a chronic productive cough. CT showed numerous pulmonary nodules with both centrilobular and perilymphatic distribution. Previous PET/CT showed stable size of the LLL nodule and numerous smaller nodules with minimal PET avidity. Repeat CT chest 5 months later showed stable nodules, no hilar or mediastinal lymphadenopathy, but with new findings of mosaic attenuation. Cocci serology was negative. The patient underwent robotic-assisted cryobiopsy of a 7.2 cm LLL nodule. Pathology revealed biopsy neuroendocrine tumorlets as well as cocci spherules and non-caseating granulomas. BAL culture was also positive for MAC. Treatment plan from tumour board discussion was to treat cocci with fluconazole, Infectious Disease management of MAC, and repeat imaging to evaluate DIPNECH. Discussion This case presents the diagnostic challenge of multiple findings via cryo biopsy resulting in DIPNECH and coinciding infection of cocci and BAL positive for MAC. All three diagnoses may present as centrilobular, perilymphatic or random/diffuse nodules on imaging. Mosaic attenuation favoring air trapping on CT also provides some overlapping between asthma and DIPNECH, which makes DIPNECH diagnostically challenging. Despite negative serology, biopsy confirmed cocci, reflecting a lower diagnostic yield of serology as first line detection of cocci exposure. In conclusion, the treatment plan became to focus on treatment of the underlying infections with continued evaluation of DIPNECH progression as pathology was positive for CAM5.2, synaptophysin, MIB-1 shows a proliferation rate of 1%, TTF1 and negative for Napsin A, no mitoses or necrosis was seen. Morphologically and immunophenotypically pathology correlated with typical carcinoid tumor / neuroendocrine tumor, grade 1 but proliferation did not meet the cut off of 5mm. This abstract is funded by: none
Vorachitti et al. (Fri,) studied this question.