A 2 – year – old child comes with discharge, seborrheic dermatitis, polyuria and hepatosplenomegaly. Which of the following is the most likely diagnosis :
Seborrheic dermatitis, polyuria, hepatosplenomegaly and discharge suggest the diagnosis of Langerhans cell histiocytosis.
Clinical manifestations of Langerhans cell histiocytosis :

It has diverse clinical features. These are

1. Skeletal involvement :

It is seen in 80% of cases (75% cases present with solitary lytic lesion).
Skull is the most common site of involvement (Presents. with solitary lytic lesion).
Involvement of the spine leads to the collapse of vertebral body and compression of spinal cord.
In flat long bones, the lesion is osteolytic.
Involvement of mastoid bones leads to chronically infected ears.

2. Skin involvement :

It is seen in 50% of patients.
It usually manifests as seborrheic dermatitis of scalp or diaper region.


3. Hepatosplenomegaly :

Seen in 20% of patients.
Manifests as jaundice and ascites.


Localized or disseminated lymphadenopathy.
Exophthalmos :


It is often B/L and is caused by retroorbital accumulation of granulomatous tissue.

Pulmonary Infiltrates :

Seen in 10-15% of patients.
The lesion consists of nodular infiltrates or diffuse fibrosis.


Endocrine → Hypopituitarism, Hypothyroidism, Diabetes insipidus.
Systemic manifestations :


Usually seen in patients affected severely.
These include fever, weight loss, malaise, irritability.
Remember these two uncommon but serious manifestations of LCH.


Cirrhosis d/t hepatic involvement.
Ataxia and dysarthria d/t CNS involvement.
Leukemia
Lymphoma
Langerhan's cell histiocytosis
Germ cell tumour