Question: What is the risk of a nonsmoking IPF patient getting lung cancer?

Answer: There are a number of manuscripts in the literature that report an increased frequency of lung cancer in patients with IPF. The reported frequency is highest in Japan (48%) and lowest in the United States (5%). The large discrepancy may include both criteria for establishing the diagnosis of IPF and distinguishing adenocarcinoma from squamous metaplasia often seen with IPF. The literature confirms that most IPF patients with lung cancer are men with a history of cigarette smoking; additionally, unknown occupational or environmental exposure may increase the risk of both IPF and lung cancer. Approximately 80% of lung cancers in IPF are located in peripheral fibrotic sites in the lower lobes, tending to implicate the inflammatory process and bronchiolar squamous metaplasia in the pathogenesis of lung cancer. Squamous cell cancer has been found to be most common in men and adenocarcinomas most common in women in IPF, although all cell types have been found in both sexes.

The pathogenesis of the apparent association of IPF and lung cancer is unclear; however, investigators have found apoptosis in IPF tissue of tumor suppressor proteins that may play a role.

While one series reported that the relative risk of developing lung cancer is 14.2 for male smokers and 6.7 for female smokers, the incidence in nonsmoking IPF patients was much lower when compared to the general population of comparable age and sex. This suggests that cigarette smoke may be an added risk factor for the development of lung cancer in IPF patients.

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Question: I have a 62 y/o female patient who was recently diagnosed with bird fancier's lung disease. She had 3 parakeets in her home for approximately 5 years, before she began to develop shortness of breath, cough, and chest discomfort. She and her husband moved out of their home and had it thoroughly cleaned, with removal of carpets and draperies, and her symptoms improved with a short course of prednisone. The birds were given to relatives. Approximately 2 months after moving back into her home, she began to experience similar symptoms. How should I treat her?

Answer: In most patients, removing bird antigens from the home will result in resolution of symptoms. However, in some instances, removal of all of the avian antigens from the home is problematic, as these antigens find their way into cracks in wood floors and other places. In this situation, I suggest that you advise your patient to move out of the home to determine the effect on her disease. If improvement occurs, she should strongly consider a permanent move. Corticosteroids may be effective in acute, severe, and progressive disease; however, their long-term efficacy has not been determined.

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Question: Do I need to do a bronchoscopic biopsy in the workup of IPF if the chest CT scan is classic with peripheral honeycombing?

Answer: The ATS/ERS statement on the diagnosis of IPF suggests that a bronchoscopy with transbronchial lung biopsy or bronchoalveolar lavage (BAL) be performed to exclude alternative diagnoses to IPF. Some have questioned whether this test is necessary in an older patient with insidious onset of dyspnea and a classic CT scan.

I find the BAL more helpful than the biopsy in this situation, provided the CT has no features to suggest sarcoidosis (significant adenopathy or fibrosis that conforms to bronchovascular distribution). The BAL should show excesses of polymorphonuclear leukocytes (> 3% of total nucleated cells), but should not show large excesses of lymphocytes or eosinophils (> 30%) that would suggest alternative diagnoses such as hypersensitivity pneumonitis (HP) or chronic eosinophilic pneumonia (CEP), respectively. It should be noted that both HP and CEP can produce a UIP pattern on the CT scan; therefore, I support the ATS/ERS statement.

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Question: I have a 68 y/o female patient with systemic mastocytosis. HRCT scan reveals diffuse reticulation with traction bronchiectasies, scanty ground glass. On biopsy, there is heterogeneous interstitial fibrosis with moderate-severe chronic inflammation with eosinophils and some mastocytes. No alveolar occupation. Pattern is similar in lower and upper lobes. Pulmonary fibrosis was previous to treatment (cromoglicate and antihystaminic). Is there any relation between systemic mastocytosis and pulmonary fibrosis?

Answer: Systemic mast cell disease is an idiopathic disorder characterized by the proliferation of mast cells in a variety of organs including the bone marrow, liver, spleen, and lymph nodes. The skin may or may not have lesions of urticaria pigmentosa. The literature does not contain any cases of clinical lung involvement from mastocytosis, including interstitial lung disease, and more specifically IPF.

However, it is not rare to see a 70 y/o individual with a preexisting chronic disease who develops IPF. On a number of occasions, I have seen patients with a known history of a chronic disease, such as sarcoidosis, who years later presented with IPF.