Acute lymphoblastic leukemia

Lymphoblastic lymphoma is an aggressive precursor lymphoid neoplasm identical to acute lymphoblastic leukemia but presenting as a mass with under 20% marrow blast involvement, classically a T-cell anterior mediastinal mass in an adolescent or young adult male causing respiratory compromise or superior vena cava syndrome. It is diagnosed by biopsy showing TdT-positive lymphoblasts and treated on ALL-type multi-agent chemotherapy protocols with mandatory central nervous system prophylaxis.

Acute myeloid leukemia is a clonal proliferation of myeloid precursors that fails to differentiate, defined by myeloblasts at or above 20% of the bone marrow or blood, and it presents with cytopenias from marrow replacement plus, in acute promyelocytic leukemia, a coagulopathic emergency. Diagnosis rests on marrow blast count, immunophenotype, and cytogenetic and molecular testing that set both classification and risk, while treatment is intensive induction chemotherapy or ATRA-arsenic trioxide for APL, followed by risk-adapted consolidation.

Chronic myeloid leukemia is a myeloproliferative neoplasm driven by the Philadelphia chromosome t(9;22), which produces the constitutively active BCR-ABL1 tyrosine kinase and marked, left-shifted granulocytosis with a low leukocyte alkaline phosphatase score. Diagnosis is confirmed by cytogenetics or molecular testing for BCR-ABL1, and a BCR-ABL tyrosine kinase inhibitor such as imatinib is first-line, continued indefinitely with molecular-response monitoring, reserving allogeneic transplant for TKI failure or blast crisis.

Tumor lysis syndrome is a metabolic oncologic emergency in which massive tumor cell breakdown, spontaneous or chemotherapy-induced, releases potassium, phosphate, and nucleic acids into the blood, producing hyperuricemia, hyperkalemia, hyperphosphatemia, and secondary hypocalcemia that can precipitate acute kidney injury, arrhythmia, seizure, and death. Risk-stratified prophylaxis with hydration plus allopurinol or rasburicase before chemotherapy, and aggressive correction of electrolytes with renal replacement therapy when needed, are the cornerstones of management.

Neutropenic fever is an oncologic emergency defined as a single oral temperature of 38.3 C or higher, or 38.0 C sustained for 1 hour, with an ANC of 500/microL or lower, most often during the chemotherapy nadir. Management is empiric antipseudomonal beta-lactam therapy within 60 minutes, with vancomycin, antifungal therapy, and growth factors added only for specific indications.

Neutropenia is a reduced absolute neutrophil count that raises infection risk sharply once the count falls below 500/microL, most often from chemotherapy or another marrow-suppressing or idiosyncratic drug. Diagnosis rests on a repeat CBC with differential and smear review followed by a directed search for cause, and management centers on stopping the offending agent, treating any underlying disease, and using G-CSF and neutropenic precautions when the count is low or the patient is febrile.

Aplastic anemia is an acquired or inherited hematopoietic stem cell disorder that produces pancytopenia with a hypocellular, fatty bone marrow and no dysplasia, blasts, or fibrosis. Diagnosis rests on marrow biopsy showing less than 25% cellularity with severity graded by the Camitta criteria, and treatment is allogeneic stem cell transplantation for young fit patients with a matched donor or antithymocyte globulin plus cyclosporine and eltrombopag for everyone else.

Non-Hodgkin lymphoma is a heterogeneous group of B-cell (about 85%) and T-cell lymphoid malignancies that spread noncontiguously and often involve extranodal sites, ranging from indolent follicular lymphoma to aggressive diffuse large B-cell lymphoma to highly aggressive Burkitt lymphoma. Diagnosis requires excisional or core biopsy with flow cytometry and cytogenetics, Ann Arbor staging with PET-CT, and treatment is subtype-specific, from observation to R-CHOP to intensive Burkitt regimens with aggressive tumor lysis and CNS prophylaxis.

Hodgkin lymphoma is a B-cell malignancy defined by Reed-Sternberg cells that classically presents with painless, contiguously spreading cervical or mediastinal lymphadenopathy in a young adult, and it is confirmed by excisional lymph node biopsy. Ann Arbor/Lugano stage and interim PET response drive risk-adapted ABVD chemotherapy with or without radiation, and most patients are cured.

Chronic lymphocytic leukemia is the most common adult leukemia, a clonal proliferation of mature B lymphocytes usually discovered as incidental lymphocytosis in older adults with smudge cells on smear. Diagnosis rests on absolute B-lymphocytosis with a characteristic flow cytometry immunophenotype, and asymptomatic early-stage disease is observed while symptomatic or progressive disease is treated with targeted agents such as ibrutinib and venetoclax.

Infectious mononucleosis is a systemic illness caused mainly by Epstein-Barr virus, presenting with fever, pharyngitis, and lymphadenopathy, confirmed by heterophile antibody or EBV-specific serology, and managed supportively with contact-sport restriction to prevent splenic rupture.

Disseminated intravascular coagulation is a secondary, systemic activation of coagulation and fibrinolysis, most often from sepsis, that simultaneously consumes platelets and clotting factors, causing microvascular thrombosis and bleeding. Diagnosis rests on a laboratory constellation, thrombocytopenia, prolonged PT and aPTT, low fibrinogen, and elevated D-dimer, in a predisposing clinical setting, and management centers on treating the underlying trigger while replacing blood components only for active or high-risk bleeding.