Lymphoma – Top USMLE Diseases

Gastric cancer is the 3rd-most common cause of cancer-related deaths worldwide. The majority of cases are from adenocarcinoma. The modifiable risk factors include Helicobacter pylori infection, smoking, and nitrate-rich diets. Hereditary syndromes, pernicious anemia, and prior partial gastrectomy are among the endogenous risk factors. When symptoms such as epigastric fullness, vomiting, and weight loss occur, it is likely that the cancer is in the advanced stage. Diagnosis is confirmed with esophagogastroduodenoscopy and biopsy. Imaging studies and laparoscopy aid in determining the cancer stage. Consequently, staging dictates the management approach. Management consists of gastrectomy and chemoradiotherapy. Most cases are diagnosed in late stages, indicating a generally poor prognosis.

Pediatric lymphomas are rare compared to other malignancies in children. They can be classified into Hodgkin's and non-Hodgkin's lymphomas. Hodgkin's lymphoma is more likely to present with systemic features such as fever, weight loss and night sweats. Non-Hodgkin's lymphoma is more likely to present with primary extranodal involvement. Histologic examination is essential in both conditions to confirm the diagnosis. Staging of the disease is important as it can change the treatment plan.

Non-Hodgkin's lymphomas (NHL) are hematological malignancies with high prevalence worldwide (accounts for about 4 % of all cancer cases and 2.7 % of all cancer deaths). They are cancers of the lymphatic tissues (mainly lymph nodes), affecting the lymphocytes, either B-cells (70 %) or T-cells/NK cells (30 %). NHLs are five times more common than the Hodgkin's lymphoma (HL). The following article discusses both B-cell type NHLs and T-cell type NHLs. 

Diffuse Large B-Cell Lymphoma (DLBCL) is the most common type of non-Hodgkin lymphoma (NHL), accounting for one-third of all NHLs in the western world. It is a very aggressive, fast-growing neoplasm unless diagnosed and treated timely (survival is less than one year without a cure). This illness is characterized by painless enlarged lymph nodes. It has a very close affiliation with genetic issues, Epstein-Barr virus (EBV) and immunocompromised conditions (congenital and acquired: HIV, AIDS).

There are two types of lymphomas - Hodgkin Lymphoma (Hodgkin`s Disease) and Non-Hodgkin Lymphoma. The follicular lymphoma belongs to the second group. It is a slow-growing B-cell lymphoma, and the second most common sub-type of NHL; most often occurs due to chromosomal translocation t(14;18) causing bcl-2 gene rearrangement. Most of the patients with FL are asymptomatic; hence they remain undiagnosed for years and usually detected in the advanced stages.

Burkitt lymphoma (small non-cleaved cell lymphoma) is one of the most aggressive and rapidly growing non-Hodgkin's lymphomas, with obvious predominance in children and young adults. This type of tumor requires urgent therapeutic intervention as the CNS and the bone marrow are involved in the malignant process since early stages of the disease.

Recently, it has become clear that cancer and our immune system communicate with each other. Because of this, our immune system eventually allows cancer cells to go unchecked, and at a certain point, cancer cells ‘escape’ our immune system's response. With this understanding, more recent anti-cancer medications are targeting the different immune checkpoints that are known to fail in identification of cancer cells.

Hodgkin lymphoma (HL) is a malignancy of B lymphocytes originating in the lymph nodes. The pathognomonic histologic finding of HL is a Hodgkin/Reed-Sternberg (HRS) cell (giant multinucleated B cells with eosinophilic inclusions). The disease presents most commonly with lymphadenopathy (neck most commonly involved), night sweats, weight loss, fever, and at times, splenomegaly and hepatomegaly. Diagnostic testing includes lymph node histologic analysis showing HRS cells, blood tests, and CT and PET scanning. HL is managed with chemotherapy and radiotherapy. The prognosis has improved significantly with the advent of chemotherapeutic regimens.