Response to transbronchial lung biopsy in diffuse parenchymal lung disease: Question still remains whether to go for surgical lung biopsy or not?

Sir,

We thank Purohit et al.[1] for their keen interest in our article “Transbronchial lung biopsy in patients with diffuse parenchymal lung disease without ‘idiopathic pulmonary fibrosis (IPF) pattern’ on high-resolution computed tomography (HRCT) scan – experience from a tertiary care center of North India” and for giving critical inputs.[2] In their comments on this article, Purohit et al.[1] have discussed the importance of surgical lung biopsy (SLB) in making the diagnosis of interstitial lung disease (ILD). We, too, do not deny that SLB is the gold standard in making the diagnosis of ILD. But, the fact that transbronchoscopic lung biopsy (TBLB) and bronchoalveolar lavage (BAL) may supply critical information that leads to a confident, specific diagnosis of many types of ILD, can not be denied (including sarcoidosis, hypersensitivity pneumonitis, eosinophilic pneumonia, organizing pneumonia, pulmonary Langerhans cell histiocytosis, lymphocytic interstitial pneumonia, pulmonary lymphangioleiomyomatosis, and pulmonary alveolar proteinosis, infections, and neoplastic processes) when these findings are combined with features of the clinical presentation and HRCT imaging.[3] A significant proportion of diagnoses obtained in our study was from this list of diseases, for which TBLB can be relied on more confidently. In our study,[1] we diagnosed tuberculosis, sarcoidosis, aspergillosis, pulmonary alveolar proteinosis, bronchoalveolar carcinoma, and lymphangioleiomyomatosis with utmost certainty.

Studies suggest that patients who are ultimately diagnosed with IPF subsequently experience worse postprocedure outcomes when compared to patients diagnosed with other forms of ILD. These data suggest that in patients suspected of having IPF, the benefits and potential complications of undergoing SLB to confirm a diagnosis must be weighed carefully against the risk of complications that are potentially life-threatening, such as triggering an acute exacerbation of IPF.[4]

If a confident diagnosis cannot be reached after an HRCT has been obtained, a less invasive approach using bronchoscopy with BAL and/or TBLB can be diagnostic and may obviate the need for proceeding to SLB.[4] SLBs are associated with a relatively low but not negligible risk of mortality and are also associated with potentially significant morbidity.[4] As Purohit et al.[1] have also listed various reasons for preferring TBLB over SLB, including advanced stage of disease, severity, comorbidities, etc., it seems rational that a trial of TBLB to be given in such selected patients before subjecting patients to a more invasive SLB. Patients diagnosed with IPF may be at somewhat greater risk of serious complications including death when subjected to SLB, and some reports suggest that SLB may trigger an acute exacerbation of the disease.[5]

Purohit et al.[1] have also raised a valid point regarding discrepancy of results in biopsy specimens, we would like to say that pathologists concluded the diagnosis after duly considering findings of each biopsy specimen.

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Conflicts of interest

There are no conflicts of interest.