Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (374 page)

   Difficulty in cross-matching blood may be encountered.

Suggested Readings

Ghobrial IM. Are you sure this is Waldenstrom macroglobulinemia?
Hematology Am Soc Hematol Educ Program.
2012;2012:586–594.

Vijay A, Gertz MA. Waldenstrom macroglobulinemia.
Blood.
2007;109:5096–5103.

HODGKIN LYMPHOMA (HL)

   Definition

HL is a neoplasm of transformed B-lymphocytes, characterized morphologically by the presence of Hodgkin or Reed-Sternberg HRS cells. In many ways, HL remains an enigmatic neoplasm.

HL is comprised of two major subgroups based on morphologic appearance and immunophenotype of the tumor cells: nodular lymphocyte predominant HL (NLPHL) and classical HL (cHL). The tumor cells of NLPHL retain the phenotypic feature of germinal center B cells, whereas they are inconspicuous in cHL. cHL is in turn subdivided into four subtypes with distinct morphology, epidemiology, and prognosis: nodular sclerosis (NSHL), mixed cellularity (MCHL), lymphocyte rich (LRHL), and lymphocyte depleted (LDHL), the latter having the worst prognosis.

   Who Should Be Suspected?

In North America and Western countries, HL has a bimodal age distribution: one peak in young adults and one in an older age group (approximately 65 years of age). Commonly, an adult with indolent lymphadenopathy, often in the cervical area. Occasionally, the patient may present with B symptoms (fever, night sweats, weight loss, and pruritus) or dyspnea in cases with advanced mediastinal involvement. Risk factors: a history of infectious mononucleosis, autoimmune disorders, immunosuppression (organ or stem cell transplantation), therapy with immunosuppressive drugs, and HIV infection.

   Laboratory Findings

   
The diagnosis of HL is based on the morphology found on excisional tissue biopsy of an involved lymph node. RS cells are large cells with slightly basophilic cytoplasm; they have bilobed or multiple nuclei, surrounded by T lymphocytes. Hodgkin cells represent the mononuclear variant
.

In addition to the laboratory tests described below,
imaging studies
have a very important role in establishing the extent of disease and differentiating HL from other conditions, especially when involving the mediastinum. Among them,
sarcoidosis
, an inflammatory disease characterized by noncaseating granulomas, involves the lungs in >90% of patients. In stage 1, sarcoidosis presents with hilar adenopathy alone, which radiologically may be very similar to HL radiographic image.

   
Bone marrow biopsy
is positive for malignant cells in up to 6.5% of advanced cases. It affects therapy only marginally.

   
CBC

   Normochromic, normocytic anemia in advanced cases. Anemia or leukopenia at presentation denotes a poor prognosis. Eosinophilia occurs in ≈20% of patients. Lymphopenia or monocytosis may also occur.

   Platelets may be decreased (in some cases, immune thrombocytopenia is present) or increased.

   
Elevated ESR, elevated LDH
, and low serum albumin are associated with advanced disease.

   
Liver function
tests may be abnormal.