This is a 68 year-old male with history of asthma and 1 year history of increasing respiratory distress and treated few months ago for pneumonia.  Open lung biopsy was performed due to recent increase in right lower lobe nodularity.

Lung Pathology

Diagnosis:

Well-differentiated adenocarcinoma arising in the background of usual interstitial pneumonia

The open lung biopsy shows a temporally heterogeneous pattern of interstitial scarring characteristic of usual interstitial pneumonia, which in the majority of cases is cryptogenic in etiology.  This histology seems to fit with the radiographic and clinical picture indicating bilateral lung disease and progressive shortness of breath. In addition to the usual interstitial pneumonia, there is evidence of a well differentiated adenocarcinoma. This diagnosis is difficult to make but several features argue for it. The areas of lung which resemble "honeycomb lung" are lined by a pseudostratified epithelium that is characterized by cells with large pleomorphic nuclei and abundant eosinophilic cytoplasm. In some areas there is architectural stratification and cribriforming. Mitotic figures are easily identified including atypical ones. These changes are typical of adenocarcinoma and there is evidence of invasion in that small glandular elements pinching off the larger dilated spaces and extending into the underlying stroma. One feature which complicates this diagnosis is that this malignant epithelium is focally in continuity with reactive bronchiolar epithelium which is ciliated and pseudostratified as well. However, the adenocarcinoma cells, while well differentiated, have nucleomegaly, irregular chromatin, and architectural features not seen in reactive bronchiolar metaplasia.

It is of some interest that reports of carcinomas arising in the setting of usual interstitial pneumonia indicate that the most common form is squamous cell carcinoma and that adenocarcinoma represents the minority of these malignancies.  Patients with carcinoma arising in usual interstitial pneumonia have a prognosis similar to patients with only usual interstitial pneumonia

This case was sent to Drs. Kevin Leslie and Henry Tazelaar of Mayo Clinic, Scottsdale, Arizona and Dr. Samuel Yousem of the University of Pittsburgh.  Both agree with the diagnosis of adenocarcinoma arising in a background of usual interstitial pneumonia.  Dr. Tazelaar graded this tumor as a grade 2 on a scale of 1 to 4 and Dr. Yousem graded this tumor as well-differentiated.

Submitted by Henry Tsai, M.D.

References:

Aubrey, et al, Mayo Clinic Proceedings 2002: 77:763-770

Comments:

I finally had a chance to read your writeup and presentation. You did an excellent job.
Good work and a nice addition to the GotPath archives. Thanks for stepping up and getting it done.