Case 27


Section 1

Look at images 1 and 2.

Image 1

What is the abnormality?

Answer

 

What is its distribution?

Answer

 

What is the relation of the vessels to the abnormality?

Answer

 

Image 2


Section 2

Gross Appearance

This slice of left lung shows the size and distribution of cysts. The cyst walls are uniformly thin. The subpleural location of some cysts accounts for the predisposition to pneumothorax.

The texture on palpation is normal, in contrast to emphysema, which is softer than normal. It is not firmer than normal as in fibrosis and honeycombing.

Also in contrast to emphysema, in which the alveolar walls collapse when fixative escapes, the cyst walls remain upright.

 


Section 3

Histologic Findings

This proliferation of smooth muscle around a small vein (V) causes focal venous obstruction. Lymphatics may also be narrowed by the muscle proliferation. These nodular proliferations are below the resolution of HRCT.

In contrast to normal smooth muscle in the lung, this muscle reacts with an antibody to a melanoma-associated antigen, HMB-45.

Find the small vein.

vein

Cystic Change

Here, perilymphatic nodules of smooth muscle appear to float in cystic spaces. An intact airway is also present. The interstitium and air spaces frequently contain hemosiderin-laden macrophages, possibly resulting from tearing of small vessels by air trapped in the cysts.

Find 2 nodules of smooth muscle.

Find a bronchiole.

nodule1nodule2bronch

Subpleural Cyst

A subpleural cystic space is surrounded by alveoli. There is no fibrous wall to the cyst. Note the RBCs in the lumen.

Find the cystic space.

cyst

Differential diagnosis of multiple lung cysts on HRCT: Lymphangioleiomyomatosis, emphysema (cysts and walls usually less well-defined), chronic interstitial lung diseases (honeycombed cysts usually peripheral), Langerhans' cell histiocytosis (nodules ± cavities, presence of thicker-walled cysts, upper lung predominance), bronchiectasis (tree-and-bud pattern often present), sarcoidosis (cysts usually apical), and pneumatoceles (commonly seen with pneumocystis pneumonia)

Histologic differential diagnosis: Lymphangioleiomyomatosis; emphysema (if smooth muscle nodules not recognized); smooth muscle proliferations such as "benign" metastasizing leiomyoma, metastatic stromal sarcoma of the uterus, and metaplastic muscle bundles in fibrosing lung diseases; and alveolar hemorrhage syndromes (if hemosiderin deposits frequent)

Diagnosis: Lymphangioleiomyomatosis

Diagnostic features of lymphangioleiomyomatosis on HRCT

Comment: HRCT is required for diagnosis of lymphangioleiomyomatosis. Progression of disease may be related to two factors: activation of matrix metalloproteinases in the proliferating cells and air-trapping [1]. Trapped air can dissect into edematous lymphatics and cause interstitial emphysema.

Reference

1. Matsui K, Takeda K, Yu Z, Travis W, Moss J, Ferrans V. Role for activation of matrix metalloproteinases in the pathogenesis of pulmonary lymphangioleiomyomatosis. Arch Pathol Lab Med 2000; 124:267-275.

Top

Next

Table of Contents

Home

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Numerous thin-walled, rounded cysts of varying size. Intervening lung is mostly normal without nodularity or architectural distortion. Note that the cyst contents are as dark as the air in the tracheobronchial tree.

Return

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Cysts are distributed evenly throughout the lungs in upper, as well as lower, lung zones.

Return

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Vessels frequently lie adjacent to, or along, the cyst wall.

Return

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Vein

Return

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Nodule of smooth muscle

Return

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Bronchiole

Return

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Cystic space

Return