METASTATIC HODGKIN'S DISEASE
Intracranial Hodgkin's disease ((ICHD) is rare. It is essential not to confuse Hodgkin's disease for other neoplasms because of its distinctive biology and treatment. Hodgkin's disease is a neoplasm of clonal Reed-Sternberg cells. Reed-Sternberg cells typically arise in lymph node tissue, probably from a deranged germinal center B-cell. Hodgkin's disease typically spreads to contiguous lymph node groups through lymphatic channels.
Intracranial Hodgkin's disease can be classified as primary cerebral Hodgkin's disease (PCHD) and secondary involvement of the cranial cavity by systemic Hodgkin's disease.
Primary cerebral Hodgkin's disease, defined as an isolated intracranial manifestation in the absence of other location, is extremely rare (2-4; 7; 8). The rarity may be related to the malignancy's origin from germinal center cells, which would be unusual to see within the brain. The number in the literature is rather small, and its existence is still controversial (6).
Most of intracranial Hodgkin's disease has been reported predominantly in patients with relapsing disease (5; 9), and rarely as an extension of the disease resistant to treatment, representing secondary involvement of the cranial cavity by systemic Hodgkin's disease. The histologic subtypes are mainly nodular sclerosis and mixed cellularity (1). Intracranial sites of disease show that dural involvement is more common than parenchymal lesions. Concurrent sites of disease at the time of intracranial presentation are predominantly within lymph nodes and bone marrow (9). The mechanism of spread to the intracranial sites from systemic Hodgkin's disease is probably hematogenous and not due to a contiguous spread from involved lymph nodes or bone marrow (9). This view is well correlated with the findings in our case which is parenchymal and angiocentric, without any evidence of direct extension from the neck lymph node.
The major neurological symptoms of intracranial Hodgkin's Disease are cranial nerve palsy, motor deficit, headache and seizure. Several therapeutic approaches have been proposed for the treatment of ICHD. Historically, surgery was the first procedure used for the treatment of neurological complications of ICHD. In the series of Dujovny et al., the average post-operative survival time as a result of surgical intervention was measured in years as opposed to months for all other treatments. However, the longest duration of survival was achieved when surgical treatment was combined with radiation therapy (5). In the series of Sapozink et al., whole brain irradiation supplemental by local boost field combined with variable combination chemotherapy, mainly MOPP and ABVD, was recommended for metastatic Hodgkin's disease (9).
Contributed by Henry G. Brown, Donald M. Whiting, E. Richard Prostko, Karl R. Fox and Jin Zhang