Thursday, February 02, 2006

Unusual presentation for BAC

A. COLE sends us the following question regarding the liklihood of a slow growing bronchioloalveolar carcinoma (BAC) metastasizing to the hilar and mediastinal lymph nodes with extremely high FDG uptake SUV:

40 yr old Female dx 7 yrs ago w/ stage 4 multifocal bronchioloalveolar carcinoma - all 3 right lobes involved. NED in left lung. Standard chemos-no effect. 6 years ago she underwent right pneumonectomy. Eight months later recurrent disease was diagnosed with multifocal nodular ground glass opacities in both lobes of the left lung.
Started Iressa and later Tarceva. Initial partial regression, followed by periods of slow growth and stability. Previously, on PET only the largest nodules show abnormal uptake, and then very mild. On recent whole body PET/CT, very slight growth of a few nodules in the left lung noted, the rest stable, and corresponding low level FDG uptake in the larger nodules (max SUV 3.2). However, for first time, lymph nodes in the hilar region and mediastinum showing intense FDG uptake (max SUV 26.7)and the left paraaortic lymph node adjacent to the crura (max SUV 30.1.).

Has anyone seen this in bronchioloalveolar carcinoma with a prior indolent course?

4 comments - CLICK HERE to read & add your own!:

Jennings said...

The only experience I've had like that was a 2 cm solitary nodule that had been followed for at *least* 2 years and was PET negative; The thought was that this was a benign nodule. At some point the patient was lost to follow-up and on re-presentation had mediastinal involvement and (if I recall) a pleural effusion with it. The diagnosis was made as BAC. Unfortunately, a repeat PET was not done so I don't know if the BAC became PET-positive.

Jeff H said...

As you've noted, BAC is usually PET negative, and is one of the classic causes of a false negative PET.

That said, it sounds as if this patient has already had a relatively agressive course of BAC, and has failed surgery and EGF receptor tyrosine kinase inhibitors (Iressa and Tarceva).

So, the following possibilities come into play:
1) These PET+ nodes are due to progression of the known BAC

2) These PET + nodes are due to an unrelated, 2nd primary malignancy

3) The PET + nodes are due to some unrelated inflammatory/infectious process.

Therapeutically, I don't know that we need to differentiate between 1 and 2, as in either case treatment options are going to be extremely limited (further salvage chemo and hope for a response versus XRT) and possibly non-existant depending on her performance status, personal wishes/goals.

So, my approach here would be to consider treating empirically for infection and discuss options for salvage chemo with an oncologist. I would consider referral for clinical trials, and discuss long term goals with the patient.

Arenberg said...

Adi Gazdar has stated that BAC is the single most overused term in lung cancer pathology reports. Many things get labelled as BAC if there is any "lepidic" growth noted on the pathology sections, but most of these are just adenos with varying levels of differentiation. The presence of mediastinal lymph node metastases virtually rules out true bronchoalveolar carcinoma, as defined by the WHO. It is possible that this lady had a "de-differentiated" adenocarcinoma, for lack of a better term.

Anonymous said...

The patient will be having a mediastinoscopy done shortly, for a definitive answer. I'll post again once we have the results.

A. Cole