Author
Van Holden, M.D.
Pulmonary and Critical Care Medicine Fellow
University of Maryland Medical Center, Baltimore, MD

Case

A 33 year-old woman with a history of uterine fibroids and iron deficiency anemia presented with progressively worsening dyspnea on exertion for 2 years. She reported shortness of breath with climbing one flight of stairs. She had an associated dry cough and intermittent sharp right-sided chest pain.

Social History: Smokes 3-5 cigarettes per day for 15 years. Drinks alcohol occasionally. Prior history of smoking marijuana. Has had 1 sexual partner.

Vital signs and cardiopulmonary exam were normal. Basic labs and EKG were also normal. Due to an elevated D-dimer of 570 ng/mL, she had a CTA chest done.

CXR and CT Chest

Question

What is the most likely etiology of her diffuse cystic lung disease?

A. Pulmonary Langerhans cell histiocytosis
B. Lymphoid interstitial pneumonia
C. Lymphangioleiomyomatosis
D. Emphysema

Answer

Correct Answer 2

Work-up revealed HIV positivity. Subsequent pathology from transbronchial biopsies was consistent with a diagnosis of lymphoid interstitial pneumonia.

The Fleischner Society defines a cyst as a "round parenchymal lucency or low-attenuating area with a well-defined interface with normal lung and a wall thickness < 2mm." A cavity, on the other hand, has a wall thickness > 2 mm. Other cyst mimics include emphysema, pneumatoceles, bronchiectasis, and honeycombing.

Differential of Cystic Lung Disease

Pulmonary Langerhans cell histiocytosis
Lymphoid interstitial pneumonia
Lymphangioleiomyomatosis
Birt-Hogg-Dubé syndrome
Erdheim Chester disease
Follicular bronchitis
Sarcomas
Pleuropulmonary blastoma
Light chain deposition disease
Amyloidosis
Sjogren syndrome
Pneumocystis jiroveci
Recurrent respiratory papillomatosis
Desquamative interstitial pneumonia
Post-traumatic pseudocysts

We review the 3 answer choices here.

	Pulmonary Langerhans cell histiocytosis	Lymphoid interstitial pneumonia	Lymphangioleiomyomatosis
Clinical characteristics	80-90% of patients are current or former smokers. Presents in young patients, M>F.	Commonly affects middle-aged women. Associated with connective tissue disorders and immunodeficiency states.	Young women. Can be sporadic or associated with tuberous sclerosis. Extrathoracic features include hepatic and renal angiomyolipomas and chylous ascites.
Presentation	About 2/3 present with cough or dyspnea. 15% present with a pneumothorax.	Cough or dyspnea	40-50% present with a pneumothorax
Histology	Peribronchiolar infiltration by the Langerhans cells, leading to stellate nodule formation	Diffuse interstitial inflammatory infiltrate, usually around lymphatics	Smooth muscle cell infiltration of the lung parenchyma, airways, lymphatics, and blood vessels
Imaging	Thick or thin-walled bizarre-shaped cysts in the upper lung that spare the costophrenic angles	Cysts are usually few in number and distributed diffusely in both lungs or primarily in the lower lung	Diffuse thin-walled cysts that are round, ovoid, or polygonal

References

Gupta N, Vassallo R, Wikenheiser-Brokamp KA, et al. Diffuse cystic lung disease part I. Am J Respir Crit Care Med 2015;191(12):1354-1366.
Gupta N, Vassallo R, Wikenheiser-Brokamp KA, et al. Diffuse cystic lung disease part II. Am J Respir Crit Care Med 2015;192(1):17-29.
Hansell DM, Bankier AA, MacMahon H, et al. Fleischner Society: Glossary of terms for thoracic imaging. Radiology 2008;246:697-722.
Jawad H, Walker CM, Wu CC, et al. Cystic interstitial lung diseases: recognizing the common and uncommon entities. Curr Probl Diagn Radiol 2014;43:115-127.

Cystic Lung Disease

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