Nodular lymphocyte predominant Hodgkin lymphoma

Hodgkin lymphoma, nodular lymphocyte predominant - low power view - H&E - by Gabriel Caponetti

Hodgkin lymphoma, nodular lymphocyte predominant - high power view - H&E - by Gabriel Caponetti

Nodular Lymphocyte Predominant Hodgkin Lymphoma (NLPHL) is a rare subtype of Hodgkin lymphoma, which itself is a type of lymphoma, a cancer originating from lymphocytes. Lymphocytes are a kind of white blood cells that are part of the immune system. NLPHL is characterized by the presence of distinctive cells known as Lymphocyte Predominant (LP) cells or "popcorn cells," which are large cells with a multilobed nucleus resembling popcorn. This condition is different from the more common Classical Hodgkin Lymphoma (CHL) in its epidemiology, pathology, clinical presentation, and treatment outcomes.

Epidemiology

NLPHL accounts for approximately 5% of all Hodgkin lymphoma cases. It has a different age distribution compared to CHL, with peaks in adolescence and late adulthood. The disease is more common in males than in females.

Pathophysiology

The hallmark of NLPHL is the presence of LP cells, which are considered to be malignant B cells. These cells are surrounded by a reactive infiltrate of benign lymphocytes, histiocytes, and occasionally eosinophils. Unlike CHL, which often involves the expression of CD30 and CD15 markers on the malignant cells, LP cells in NLPHL typically express B-cell markers such as CD20 and CD45.

Clinical Presentation

Patients with NLPHL usually present with painless lymphadenopathy, most commonly affecting cervical and axillary lymph nodes. Systemic symptoms such as fever, night sweats, and weight loss (B symptoms) are less common than in CHL. The disease is often diagnosed at an early stage and tends to follow an indolent course, with slow progression.

Diagnosis

The diagnosis of NLPHL is based on the histological examination of a lymph node biopsy. The presence of LP cells in a nodular pattern is key to the diagnosis. Immunohistochemistry is used to distinguish NLPHL from CHL and other lymphomas, with LP cells showing positivity for B-cell markers and negativity for CD15 and CD30.

Treatment

The treatment of NLPHL depends on the stage and symptoms of the disease. For early-stage NLPHL, localized radiotherapy is often the treatment of choice. Advanced stages may require chemotherapy, with or without radiotherapy. The use of rituximab, a monoclonal antibody targeting CD20, has shown promise in the treatment of NLPHL, especially in relapsed or refractory cases.

Prognosis

The prognosis for patients with NLPHL is generally favorable, with high rates of long-term survival. However, the disease can recur, and patients require long-term follow-up. There is also an increased risk of developing secondary malignancies, including non-Hodgkin lymphoma and solid tumors.

Conclusion

Nodular Lymphocyte Predominant Hodgkin Lymphoma is a distinct entity within the spectrum of Hodgkin lymphoma, with unique clinical and pathological features. Despite its indolent nature, careful diagnosis and appropriate treatment are essential to manage the disease effectively and to monitor for potential complications.