Honeycomb lung, gross specimen. Honeycomb lung is a long-term consequence of fibrosis. Areas of lung tissue are converted into multiple cyst-like spaces, separated from each other by fibrous tissue. Pneumonia, inhalation of toxins, some drugs and some rheumatoid diseases can all result in lung fibrosis. Respiration is impaired and in severe cases pulmonary hypertension contributes to heart failure.