Langerhans Cell Histiocytosis (LCH)

Question 1

What is Langerhans cell histiocytosis?

Answer 1

Langerhans cell histiocytosis

• neoplasm of immature dendritic cells (Langerhans cells)
• “tennis racket” appearing Birbeck granules on electron microscopy
• CD1a⁺ and S-100⁺

Question 2

What are the main types of Langerhans cell histocytosis?

Answer 2

• multifocal/multisystem (Letterer-Siwe)
• unifocal and multifocal unisystem (eosinophilic granuloma)
• pulmonary Langerhans cell histiocytosis

Question 3

What is the common presentation of multifocal/multisystemic Langerhans cell histiocytosis (Letterer-Siwe disease)?

Answer 3

• <2 y/o; can affect adults
• skin rash resembling seborrheic reuption
• lesions present in multiple organ systems

Question 4

What is the expected prognosis of multifocal/multisystemic Langerhans cell histiocytosis (Letterer-Siwe disease)

Answer 4

• rapily fatal if untreated
• w/ treatment, 50% 5 year survival

Question 5

What is the common presentation of unifocal and multifocal unisystem Langerhans cell histiocytosis (eosinophilic granuloma)?

Answer 5

Eosinophils present in addition to Langerhan cells

Unifocal:

-patholgic fractures in adolescents

Multifocal unisystem:

-pathologic fractures in young children

-Hand-Schuller-Christian tirad (calverial bone defects, diabetes insipidus, exopthalmos)

Question 6

What is the expected prognosis of unifocal and multifocal unisystem Langerhans cell histiocytosis (eosinophilic granuloma)?

Answer 6

spontaneous regression can occur

multifocal -> chemotherapy

unifocal -> excision/radiation

Question 7

What is the common presentation of pulmonary Langerhans cell histiocytosis?

Answer 7

-typically adult smokers

-multiple nodules in lungs

Question 8

What is the expected prognosis of pulmonary Langerhans cell histiocytosis?

Answer 8

-can regress with cesation of smoking

Question 9

What B cell neoplasm is CD5⁺?

Answer 9

chronic lymphocytic leukemia (CLL)