Correct!
1. Bronchoscopic biopsy
Among the choices listed, bronchoscopic biopsy is the most appropriate. Cervical mediastinoscopy is useful for the evaluation of the mediastinum, particularly inferior to the carina, but would be of little use for a patient without mediastinal abnormalities. Medical pleuroscopy would not be useful for this patient as no pleural abnormalities are present. Open surgical lung biopsy would surely establish a diagnosis for this patient but is overly invasive at this point, and could be considered if transbronchial bronchoscopic biopsy is unrevealing and thoracoscopic lung biopsy cannot be performed. Percutaneous transthoracic needle and core biopsy is a very useful procedure for obtaining lung tissue for diagnosis, but is typically only employed for focal lung disorders, not diffuse lung diseases.
The patient underwent flexible fiberoptic bronchoscopy with transbronchial biopsy, which disclosed mixed inflammation with eosinophils and histiocytes. The histiocytes stained positively for CD1a, CD68, and S-100, with no staining for Factor XIII. These staining parameters were consistent with Langerhans cell histiocytosis. Further immunohistochemical analysis, however, showed no staining with CD207, which usually stains positive for LCH. Therefore the histopathological and immunohistochemical analysis was consistent with Indeterminate cell histiocytosis. Another biopsy of the focal skin lesions was performed and showed a similar staining pattern, with dendritic cell features showing extensive immunoreactivity for CD11c, HLA-DR, CD1a, and CD68, the latter consistent with macrophage differentiation. The final diagnosis was established as indeterminate cell histiocytosis, with multicentric disease.
Diagnosis: Non-Langerhans cell (intermediate cell) histiocytosis
Post-Script: Bone marrow biopsy, peripheral blood flow cytometry, nuclear skeletal scintigraphy, and CT of the abdomen and pelvis were performed and were normal. The patient was treated with methotrexate and ultraviolet light therapy for her skin lesions, and the skin lesions and nodules seen at thoracic CT (Figure 6) nearly completely resolved.
Figure 6. Left: Representative static images from repeat axial HRCT just over a year following the presentation HRCT (Figure 4) and following methotrexate therapy shows significant improvement in the nodular lung disease.Right: video of axial HRCT.
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