Discussion
Diagnosis With Brief Discussion
- Diagnosis
- Langerhans cell histiocytosis (LCH)
- Radiologic Findings
- Chest radiograph shows multiple small nodules and thin-walled cystic lesions in upper and middle lungs. Chest CT images show multiple small cystic or cavitary nodules in both lungs, especially upper lobes while relatively sparing of lung base. There are no pneumothorax, pleural effusion, and thoracic lymphadenopathy. On chest CT 1 year ago, there was no lesion.
In this case, the patient has been following up for rectal neuroendocrine tumor (NET), and multiple cystic nodules were newly developed when compared with previous chest CT 1 year ago. The patient was asymptomatic. His medical record revealed that he was a 30 pack-year current smoker. Through this, we could think of pulmonary LCH and cystic metastasis as a differential diagnosis.
- Brief Review
- He underwent VATS wedge resection of the right upper and lower lobe and was finally diagnosed with pulmonary Langerhans cell histiocytosis. On pathologic specimens, the tissue was composed of a densely cellular infiltrate of histiocytes and other inflammatory cells within the interstitium and air space. Langerhans cell aggregates were highlighted by positive immunohistochemical staining for CD1a. At higher magnification, sheets of histiocytes (arrows) with abundant pale, eosinophilic cytoplasm (arrowhead) were apparent.
Langerhans cell histiocytosis (LCH) is a rare disease of unknown etiology, characterized by organ infiltration with specialized myeloid cells, which share morphological and surface receptor markers with epidermal Langerhans cells (LCs). Pulmonary LCH refers to LCH isolated to the respiratory system, notably the lungs. In adults, PLCH occurs predominantly in young smokers or ex-smokers (>90% of cases), with a peak incidence between the ages of 20 and 40 years. PLCH occurs with equal frequency in both genders.
There are for key elements concerning the pathogenesis of PLCH: (1) the mechanisms of accumulation of large numbers of CD1a+ cells in bronchiolocentric loosely formed granulomas; (2) the capacity of these granulomatous lesions to destroy and remodel surrounding tissues; (3) the reactive versus clonal/neoplastic nature of the disease; and (4) the role of smoking in adult PLCH.
The radiologic findings of pulmonary LCH vary depending on the stage of the disease at diagnosis.
The radiographic findings of LCH include reticular, nodular, and reticulonodular patterns, often in combination; a cystic appearance may mimic honeycombing. Abnormalities usually are bilateral, predominantly involving the middle and upper lung zones, with relative sparing of costophrenic angles.
In the early stage of the disease, only small nodules (usually smaller than 10 mm) may be seen, with a peribronchiolar distribution. Cavitation may be present in as many as 10% of patients. The classic CT manifestation includes cysts of varying size and thickness, with scattered peribronchiolar nodules. As the disease progress, cysts predominate and appear thin-walled, an appearance very similar to that of emphysema.
Histologically, PLCH may have different appearances depending on the stage of the disease. In the early stages, lesions are predominantly cellular, with a high concentration of Langerhans cells, eosinophils, and various inflammatory cells. Langerhans cell nuclei have a typical folded appearance and are positive for CD1, S-100, and E-cadherin stains. Langerhans cells also contain Birbeck granules, which appear as pentalaminar rods or racquet-shaped inclusions at electron microscopy. As the disease progresses, the cellular component decreases and is replaced by collagen, leading to fibrosis and the “burned-out” lesion typically described as a peribronchiolar stellate scar.
Smoking cessation is of paramount importance in treating PLCH, with stabilization occurring in most patients and regression occurring in 10%–15% of patients who quit smoking. For those in whom the disease progresses, corticosteroid and immunosuppressive therapy may be of use.
- Please refer to
Case 980, Case 904, Case 849, Case 717, Case 587, Case 422, -
KSTR imaging conference 2018 Summer Case 6
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KSTR Imaging Conference 2015 Spring Case 2
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KSTR Imaging conference 2009 Summer Case 9
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KSTR Imaging Conference 2002 Summer Case 5
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KSTR Imaging Conference 2000 Case 4,
- References
- 1. Verssallo R, Harari S, Tazi A. Current understanding and management of pulmonary Langerhans cell histiocytosis. Thorax 2017; 72:937–945.
2. Danny L, Darel E, Robert El. Best cases from the AFIP, Pulmonary Langerhans Cell Histiocytosis. RadioGraphics 2007; 27:265–268.
3. Alison C, Miller K, Farver C, et al. AIRP Best Cases in Radiologic Pathologic Correlation: Pulmonary Langerhans Cell Histiocytosis. RadioGraphics 2012; 32:987–990.
- Keywords