HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Donnelly, L. F. Articles by Frush, D. P. Search for Related Content PubMed PubMed Citation Articles by Donnelly, L. F. Articles by Frush, D. P. Social Bookmarking                      What's this?

Langerhans' Cell Histiocytosis Showing Low-Attenuation Mediastinal Mass and Cystic Lung Disease

Children's Hospital Medical Center and the University of Cincinnati Cincinnati, OH 45229-3039, Duke University Medical Center Durham, NC 27710

A 19-month-old girl presented with a 6-month history of progressive dyspnea, weight loss, and failure to thrive. Chest radiographs showed multiple cystic lucencies within the lungs bilaterally and diffusely. CT was performed to further evaluate the cystic lung changes. CT scans showed multiple thin-walled cysts (Fig. 5A) with extensive upper and lower lung involvement. Additional findings included a low-attenuation masslike enlargement of the thymus (Fig. 5B) with enhancing septa. In the liver, periportal low-attenuation and focal low-attenuation lesions were found (Fig. 5C).

View larger version (125K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 5A. —Langerhans' cell histiocytosis in 19-month-old girl. Contrast-enhanced CT scan shows low-attenuation thymic mass (arrows) with enhancing septations.

View larger version (104K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 5B. —Langerhans' cell histiocytosis in 19-month-old girl. CT image (lung windows) shows multiple lung cysts.

View larger version (119K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 5C. —Langerhans' cell histiocytosis in 19-month-old girl. CT image through liver shows periportal low attenuation (large arrows) and areas of focal low attenuation (small arrows).

Such extensive cystic lung disease resulting from an unknown cause is extremely uncommon in a 19-month-old child. One of the primary differential considerations for the cystic lung disease and liver involvement was Langerhans' cell histiocytosis. However, we were unaware of an association between the presence of a thymic mass and Langerhans' cell histiocytosis. The presence of this low-attenuation thymic mass with enhancing septations led us to consider other diagnoses such as the multilocular thymic cysts associated with HIV infection in children [1]. The cystic lung disease might also be explained on an infectious basis such as pneumocystis in an immunocompromised child. However, findings of an immunologic work up, including HIV testing of the patient and parents, were negative. Thoracoscopic biopsies of the thymus and lung were performed. The lung biopsy showed histologic changes consistent with Langerhans' cell histiocytosis. Evaluation with electron microscopy showed Birbeck granules, confirming the diagnosis. The healthy architecture and lymphoid tissue of the thymus were completely replaced by a fibroxanthomatous reaction and small aggregates of Langerhans' cells.

Abnormal morphologic changes in the thymus of children with Langerhans' cell histiocytosis are well documented [2]. Abnormalities include severe dysplasia, dysmorphia, and severe nonspecific involution [2]. Functional thymic deficiency has also been described. Several reports have described abnormal changes seen on CT scans in children with Langerhans' cell histiocytosis [3,4]. However, these reports have emphasized the presence of thymic calcifications as the key imaging finding. Our patient showed a low-attenuation multiseptated cystic-appearing mass without the presence of calcifications. The low attenuation seen on CT scans was related to increased fatty content caused by replacement of healthy thymic tissue with fibroxanthomatous reaction. The presence of a low-attenuation mass should not preclude the diagnosis of Langerhans' cell histiocytosis when other findings are consistent with the diagnosis.

References

1. Leonidas JC, Berdon WE, Valderrama E, et al. Human immunodeficiency virus infection and multilocular thymic cysts. Radiology 1996;198:377-379[Abstract/Free Full Text]
2. Newton WA Jr, Hamoudi AB, Shannon BT. Role of the thymus in histiocytosis-X. Hematol Oncol Clin North Am 1987;1:63-74[Medline]
3. Sumner TE, Auringer ST, Preston AA. Thymic calcifications in histiocytosis X. Pediatr Radiol 1993;23:204-205[Medline]
4. Odagiri K, Nishihira K, Hatekeyama S, Kobayashi K. Anterior mediastinal masses with calcifications on CT in children with histiocytosis-X (Langerhans' cell histiocytosis): report of two cases. Pediatr Radiol 1991;21:550-551[Medline]

CiteULike

Complore

Connotea

Del.icio.us

Digg

Reddit

Technorati

This Article Figures Only Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Donnelly, L. F. Articles by Frush, D. P. Search for Related Content PubMed PubMed Citation Articles by Donnelly, L. F. Articles by Frush, D. P. Social Bookmarking                      What's this?