Oncology Review: Sarcomas, Central Nervous System, and Head & Neck Malignancies

Comprehensive vocabulary flashcards covering the etiology, anatomy, presentation, staging, and radiation oncology treatment principles for bone and soft tissue sarcomas, central nervous system neoplasms, and head and neck carcinomas.

Osteosarcoma

The most common primary osseous malignant bone tumor in children, occurring most frequently in young males between ages $10$ and $30$ (peaking in the teenage years), most commonly arising in the distal femur and proximal tibia.

Ewing Sarcoma

A malignant tumor of the appendicular skeleton (predominantly the pelvis and femur) characterized histologically by sheets of small, blue, round cells with a high nuclear-to-cytoplasmic ratio and linked to alterations in the $TP53$ gene.

Chondrosarcoma

A malignant bone tumor arising from mesenchymal elements of bone, located predominantly in the pelvis and femur, for which surgical resection is the primary treatment because chemotherapy has no substantial effect.

Multiple Myeloma

A malignant proliferation of plasma cells (B-cell lymphocytes) characterized by widespread osteolytic bone lesions, pathologic fractures, and hypercalcemia, most commonly diagnosed in patients older than $65$ years.

Geographic Bone Destruction

A benign or less aggressive pattern of bone destruction presenting as a uniformly affected area with sharply defined, well-demarcated borders.

Permeative Bone Destruction

An aggressive, rapid pattern of bone destruction characterized by ill-defined, punctate radiolucencies that infiltrate cortex and marrow, typically seen in round cell malignancies such as Ewing sarcoma.

Osteolytic Lesions

Pathologic skeletal lesions that actively break down and destroy bone tissue, leaving the affected bone weakened, porous, and full of holes.

Osteoblastic Lesions

Pathologic skeletal lesions that stimulate excess new bone matrix deposition, making the bone abnormally dense and hard.

Pseudocapsule (Soft Tissue Sarcoma)

A zone of compressed normal and neoplastic cells formed as a soft tissue tumor expands; it must not be breached during excision because it represents the primary zone for local disease recurrence.

Rhabdomyosarcoma

The most common histologic subtype of soft tissue sarcoma occurring in pediatric patients, arising from mesenchymal stem cells.

Liposarcoma

One of the two most common histological types of soft tissue sarcoma in adults, arising from mesenchymal adipose tissue.

Intralesional Resection

A surgical approach in which the incision enters within the tumor mass itself, leaving gross residual tumor behind.

Marginal Resection

A surgical resection that cuts directly through the surrounding pseudocapsule or reactive zone, leaving microscopic residual tumor foci behind.

Wide Excision

A surgical technique that removes the tumor along with an intact cuff of surrounding normal tissue outside the pseudocapsule, leaving no residual tumor other than potential skip metastases.

Tentorium Cerebelli

A transverse fold of dura mater that separates the cerebral hemispheres (supratentorial space) from the cerebellum (infratentorial space).

Dura Mater

The tough, fibrous outermost layer of the cranial meninges containing blood vessels and nerves that protects the brain and spinal cord.

Arachnoid Mater

The avascular middle meninx located between the dura mater and the pia mater that lacks blood vessels.

Pia Mater

The thin, vascular innermost meninx adhering directly to the surface of the brain and spinal cord, containing nerves and blood vessels that nourish underlying neural parenchyma.

Microglial Cells

Specialized neuroglial cells of the central nervous system that provide neural support and phagocytize bacterial cells and cellular debris.

Astrocytes

Star-shaped neuroglial cells that provide structural support, regulate interstitial concentrations of ions and nutrients, and proliferate to form scar tissue following CNS injury.

Oligodendrocytes

Neuroglial cells of the central nervous system responsible for producing the insulating myelin sheaths that surround axons in the brain and spinal cord.

Schwann Cells

Peripheral nervous system neuroglial cells that produce the lipid-rich myelin sheath surrounding peripheral nerve axons.

Meningioma

The most common benign intracranial tumor, originating from the membranous meninges that envelop the brain and spinal cord.

Glioblastoma Multiforme (GBM)

The most aggressive, invasive, and lethal primary malignant glial brain tumor in adults (WHO Grade IV), associated with a $3\text{-year}$ survival rate of approximately $2.2\%$.

Medulloblastoma

A malignant primitive neuroectodermal brain tumor arising in the cerebellum of children with a strong propensity to seed the neuraxis via cerebrospinal fluid (CSF).

Craniospinal Axis Irradiation (CSI)

A radiation technique that treats the entire brain with opposed lateral fields and the entire spinal cord with a posterior field, feathering junctional field gaps by $1\,cm$ every $1000\,cGy$ to avoid hotspots.

Blood-Brain Barrier (BBB)

A specialized physiological capillary barrier in the central nervous system that restricts toxic compounds and large molecules from entering brain tissue, requiring therapeutic agents to be lipid soluble to penetrate.

Jugulodigastric Lymph Node

Also called the subdigastric node, a primary Level II deep cervical lymph node situated below the posterior belly of the digastric muscle that receives extensive drainage from the tonsils, pharynx, and oral cavity.

Node of Rouviere

The lateral retropharyngeal lymph node positioned at the skull base that serves as the initial draining lymph station for nasopharyngeal carcinomas.

Level II Cervical Lymph Nodes

The upper jugular lymph node group (upper jugulodigastric chain) extending from the base of the skull to the inferior border of the hyoid bone.

Level V Cervical Lymph Nodes

The posterior triangle nodal group containing the spinal accessory nerve chain and transverse cervical nodes, bounded by the sternocleidomastoid, trapezius, and clavicle.

Lymphoepithelioma

A poorly differentiated nonkeratinizing variant of squamous cell carcinoma (WHO Type 3) of the nasopharynx strongly linked to Epstein-Barr Virus (EBV), exhibiting greater radiosensitivity and better clinical outcomes than keratinizing forms.

Plummer-Vinson Syndrome

A clinical syndrome characterized by chronic iron-deficiency anemia, esophageal webs, and dysphagia that carries an increased risk of tongue and postcricoid hypopharyngeal carcinomas.

Glottic Carcinoma

A malignancy arising on the true vocal cords (accounting for $65\%$ of all laryngeal cancers) presenting early with hoarseness, possessing virtually no lymphatic capillary drainage, and rarely spreading to regional nodes.

Supraglottic Larynx

The superior anatomical region of the larynx located above the true vocal cords (including the epiglottis, false vocal cords, ventricles, and aryepiglottic folds) that has rich bilateral lymphatic drainage.

Hemiglossectomy

The surgical resection of one lateral half of the tongue, utilized primarily for resectable squamous cell carcinomas confined to the anterior two-thirds of the oral tongue.