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Neuroradiology Case of the Week

Case 162

Ajay Malhotra , MD, Ravinder Sidhu, MD and PL Westesson MD, DDS, PhD

Clinical Presentation: A six-year-old female with recent onset of headaches of increasing severity and diabetes insipidus.

Radiological Findings: There is thickening of the pituitary infundibular stalk with the lesion extending inferiorly and expanding the pituitary gland and superiorly extending into hypothalamus. The stalk measures 5-8 mm. There is loss of the posterior pituitary bright spot on T1W images. The thickened infundibulum is isointense to grey matter. Sagittal and coronal post-gadolinium images demonstrate intense, homogeneous enhancement of the abnormal soft tissue involving the infundibulum.
     Patient also had cystic lesions and nodules in the lung. She underwent skin biopsy of the scalp which was diagnostic for Histiocytosis X. She received radiation treatment for the hypothalamic-pituitary axis lesion.

Differential Diagnosis: Thickened , enhancing Infundibular stalk-

• Langerhans Cell Histiocytosis
• Germinoma
• Sarcoid
• Glioma
• Lymphoma
• Tuberculosis
• Metastatic disease

Diagnosis: Langerhans Cell Histiocytosis (Histiocytosis X)

Discussion: Langerhans cell histiocytosis (LCH) is a rare disease characterized by aberrant proliferation of a specific dendritic (Langerhans) cell belonging to the monocyte-macrophage system. These atypical but mature cells of monoclonal origin can infiltrate many sites of the body and may occur as localized lesions or as widespread systemic disease. Infiltration of the hypothalamic-pituitary axis (HPA) has been reported in between 5–50% of autopsy patients with LCH. Diabetes insipidus (DI) is the most common endocrine abnormality, reported in 15–50% of patients with LCH.
     Generalized hypothalamic involvement is also a prominent feature of this disease, and the progressive hypopituitarism appears to be poorly responsive to current modalities of treatment, although localized disease at the HPA responds well to radiotherapy in that region.
     Patients with LCH and DI, particularly those with multisystem disease and a structural lesion on radiology, should undergo regular and prolonged endocrine assessment to establish anterior pituitary deficiency and provide appropriate hormonal replacement.

References:

1. Kaltsas GA, Powles TB, Evanson J, Plowman PN, Drinkwater JE, Jenkins PJ, Monson JP, Besser GM, Grossman AB. Hypothalamo-pituitary abnormalities in adult patients with langerhans cell histiocytosis: clinical, endocrinological, and radiological features and response to treatment. J Clin Endocrinol Metab. 2000 Apr;85(4):1370-6. [Medline]
2. Dunger DB, Broadbent V, Yeoman E, Seckl JR, Lightman SL, Grant DB, Pritchard J.The frequency and natural history of diabetes insipidus in children with Langerhans-cell histiocytosis. N Engl J Med. 1989 Oct 26;321(17):1157-62. [Medline]
3. Broadbent V, Dunger D, Yeomans E, Kendall B. Anterior pituitary function and computed tomography/magnetic resonance imaging in patients with Langerhans cell histiocytosis and diabetes insipidus. Med Pediatr Oncol. 1993;21(9):649-54. [Medline]