Histogenesis of Tumors – Vocabulary

Vocabulary flashcards summarizing key tumor types, pathologic features, classifications, and related concepts from the BMS-102 lecture on Histogenesis of Tumors.

Histogenesis of Tumor

Study of the tissue origin and development of neoplasms (epithelial, mesenchymal, miscellaneous).

Benign Tumor

Neoplasm that remains localized, is usually well-circumscribed, grows slowly, and does not metastasize.

Malignant Tumor

Neoplasm that invades locally, may destroy tissue, grows rapidly, and can metastasize.

Locally Malignant Tumor

Neoplasm that is invasive and destructive locally but rarely metastasizes (e.g., basal cell carcinoma).

Carcinoma

Malignant tumor of epithelial origin.

Sarcoma

Malignant tumor of mesenchymal (connective-tissue) origin.

Papilloma

Benign tumor of surface (protective) epithelium forming finger-like projections; often HPV-related.

Adenoma

Benign tumor of secretory ‘glandular’ epithelium; may be solid or cystic (cystadenoma).

Adenopapilloma / Adenomatous Polyp

Benign tumor of secretory-protective epithelium, common in colorectum; risk of adenocarcinoma.

Squamous Cell Carcinoma (SCC)

Malignant tumor of squamous epithelium; graded by keratin pearl (cell-nest) formation.

Broder’s Classification

SCC grading based on % keratin nests: Grade I (75–100%) to Grade IV (0–25%).

Keratin Pearl

Concentric layers of keratinizing squamous cells seen in well-differentiated SCC.

Adenocarcinoma

Malignant tumor of gland-forming epithelium; may appear ulcerative, infiltrative, or cauliflower-like.

Cystadenocarcinoma

Adenocarcinoma in which malignant cells line and invade cystic spaces.

Papillary Cystadenocarcinoma

Cystic adenocarcinoma containing papillary fronds lined by malignant epithelium.

Mucoid (Colloid) Adenocarcinoma

Adenocarcinoma producing abundant mucin pools with signet-ring cells; poor GIT prognosis.

Signet Ring Cell

Malignant cell distended by mucin displacing nucleus to one side.

Basal Cell Carcinoma (BCC)

Locally malignant tumor of epidermal basal cells; forms ‘rodent ulcer’ and shows peripheral palisading.

Rodent Ulcer

Classic ulcerative lesion of BCC with raised beaded edge and local tissue destruction.

Basaloid Cells

Small, dark epithelial cells characteristic of BCC sheets and nests.

Peripheral Palisading

Alignment of tumor cell nuclei at periphery of BCC nests parallel to each other.

Fibroma

Benign tumor of fibrous connective tissue.

Fibrosarcoma

Malignant tumor of fibrous connective tissue.

Lipoma

Common benign tumor of mature adipose tissue; often subcutaneous.

Osteoma

Benign, hard, compact bone tumor of skull/face; may cause pressure symptoms.

Osteoid Osteoma

Painful benign bone tumor (<1 cm) of young males; prostaglandin-mediated pain relieved by salicylates.

Osteosarcoma

Highly malignant bone-forming tumor (not detailed in notes but counterpart of osteoma).

Chondroma (Osteochondroma)

Benign cartilage-capped bony projection (exostosis) from metaphysis; may be multiple and turn malignant.

Enchondroma

Benign intramedullary cartilage tumor of short/flat bones; can fracture or become chondrosarcoma.

Leiomyoma

Benign smooth-muscle tumor (e.g., uterus); shows whorled bundles of spindle leiomyocytes.

Fibrovascular Core

Connective-tissue stalk containing vessels, typical in papilloma papillae.

Hemangioma

Benign vascular tumor; capillary or cavernous types.

Capillary Hemangioma

Composed of small capillary-sized vessels; variants include port-wine stain, strawberry, cherry spots.

Cavernous Hemangioma

Composed of large dilated vascular spaces; common in liver and skin.

Lymphangioma

Benign tumor of lymphatic vessels forming ill-defined, doughy masses with clear lymph.

Cystic Hygroma

Large cavernous lymphangioma; may obstruct labor; neck/axilla common.

Fibromatosis

Locally aggressive fibrous tissue proliferation; considered locally malignant.

Giant Cell Tumor of Bone

Locally malignant bone tumor composed of osteoclast-like giant cells.

Adamantinoma

Locally malignant tumor of jaw resembling ameloblastoma.

Melanocytic Nevus (Mole)

Benign tumor of melanocytes; may be junctional, intradermal, or compound.

Lentigo

Flat hyperpigmented lesion where melanocytes replace basal layer; not a nevus but related.

Junctional Nevus

Nevus cells at epidermal-dermal junction; higher melanoma risk.

Intradermal Nevus

Nevus cells only in dermis; common in adults; least melanoma risk.

Compound Nevus

Nevus with cells in both junction and dermis.

Malignant Melanoma

Highly malignant tumor of melanocytes; prognosis correlates with vertical growth (Breslow depth).

ABCDE Criteria

Clinical warning signs of melanoma: Asymmetry, Border irregularity, Color variegation, Diameter >6 mm, Evolving.

Breslow Depth

Measurement in mm from granular layer to deepest melanoma cell; major prognostic factor.

Clark’s Levels

Melanoma staging by anatomic skin level I–V; historical prognostic system.

Mixed Tumor (True)

Neoplasm with two or more neoplastic components from same germ layer, e.g., fibroadenoma of breast.

Pleomorphic Adenoma

Mixed tumor of salivary gland with epithelial and myxochondroid stromal elements.

Adenoacanthoma

Adenocarcinoma containing benign squamous metaplastic areas.

Adenosquamous Carcinoma

Malignant tumor containing both adenocarcinoma and malignant squamous components.

Embryonal Tumor (Blastoma)

Highly malignant tumor of immature cells showing organogenesis; radiosensitive; named with ‘-blastoma’ suffix.

Medulloblastoma

Embryonal tumor of cerebellum in children.

Retinoblastoma

Embryonal malignant tumor of retinal photoreceptor precursor cells.

Neuroblastoma

Embryonal tumor of adrenal medulla or sympathetic ganglia.

Nephroblastoma (Wilms Tumor)

Embryonal renal tumor of childhood.

Hepatoblastoma

Embryonal malignant tumor of liver in infants/children.

Embryonal Rhabdomyosarcoma

Malignant skeletal-muscle tumor seen in nose, bladder, vagina, etc.

Teratoma

Tumor containing tissues from all three germ layers; arises from totipotent germ cells.

Mature Teratoma (Dermoid Cyst)

Benign cystic ovarian teratoma lined by squamous epithelium with skin appendages.

Immature Teratoma

Predominantly solid teratoma containing immature tissues; malignant.

Monodermal Teratoma (Struma Ovarii)

Teratoma composed predominantly of one tissue type, e.g., thyroid tissue in ovary.

Apudoma / Neuroendocrine Adenocarcinoma

Malignant tumor of diffuse neuroendocrine (APUD) system; includes carcinoid tumors.

Carcinoid Tumor

Well-differentiated neuroendocrine tumor of GI tract or bronchus; may secrete serotonin.

Paraneoplastic Syndrome

Symptoms caused by tumor-secreted factors remote from primary/site of metastasis (e.g., SIADH in small-cell lung cancer).

SIADH

Syndrome of inappropriate antidiuretic hormone secretion; hyponatremia often from small-cell lung carcinoma.

CA19-9

Serum tumor marker elevated in pancreatic carcinoma.

Carcinoembryonic Antigen (CEA)

Oncofetal glycoprotein elevated in colorectal, pancreatic, gastric, and other cancers.

Carcinoma in Situ

Full-thickness epithelial malignancy without basement membrane invasion; precursor to invasive cancer.

Dysplasia

Disordered, potentially reversible epithelial growth with cytologic atypia; may progress to carcinoma in situ.

Tumor Grade

Degree of histologic differentiation and mitotic activity of tumor cells.

Tumor Stage

Extent of tumor spread (size, nodal involvement, metastasis); assessed clinically/radiologically.

Desmoplastic Reaction

Fibrous stromal response to invasive carcinoma.

Desmosome (Prickling)

Intercellular adhesion seen in squamous cells; lost in poorly differentiated SCC.

HPV Types 1, 2, 4, 7

Low-risk human papillomavirus strains associated with squamous papillomas.

Actinic Keratosis

Premalignant sun-induced epidermal dysplasia that may progress to cutaneous SCC.

Port-Wine Stain

Flat capillary hemangioma presenting as purple-red skin patch.

Strawberry Hemangioma

Raised bright-red capillary hemangioma of infancy; often regresses.

Cherry Hemangioma

Small dome-shaped red papule; common adult capillary hemangioma.

Metaplasia

Reversible change where one differentiated cell type is replaced by another; may occur within tumors.

Capsule (Tumor)

Fibrous rim surrounding many benign tumors, aiding surgical enucleation.

Epithelial vs. Mesenchymal Arrangement

Carcinoma cells in groups/nests; sarcoma cells often singly dispersed; helps microscopic distinction.