Answer 1
C. CD1a
Answer 2
D. Langerhans cell histiocytosis (histiocytosis X)
Comment
Langerhans cell histiocytosis—also known as histiocytosis X or eosinophilic granuloma—is an unusual condition of ubiquitous distribution that may be seen in different anatomic sites including lymph nodes, lung, and bone, among others.
It is commonly seen in children with lesions in the bone. However, the lesion may also affect adult individuals and it may be limited to the lymph nodes.
The histological features are rather characteristic and the use of immunohistochemical stains mainly S-100 protein and CD1a would help in the defining the diagnosis.
