adenocarcinoma

DEFINITION of adenocarcinoma

adenocarcinoma is cancer arising from glandular epithelium, forming gland‑like structures or secreting mucin. Adenocarcinoma is a malignant tumor of epithelial origin derived from glandular or secretory epithelium (endoderm, mesoderm, or ectoderm), exhibiting morphological features such as glandular/acinar differentiation, mucin production, or ductal structures. It represents the most common type of non‑small cell lung cancer (NSCLC), colorectal cancer, pancreatic cancer, esophageal cancer, and many others, with subtypes including mucinous, signet‑ring cell, papillary, bronchioloalveolar (now reclassified), and others based on histologic patterns and molecular features.

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ETYMOLOGY of adenocarcinoma

greek • Adeno-: Greek adēn, adēn‑ = “gland” (cf. adenoma). • Carcin-: Greek karkinos = “crab” (due to vein pattern resembling crab legs; → Latin cancer). • -oma: Greek ‑oma = “tumor, growth.” • Literal meaning: “Glandular tumor” or “gland cancer.”

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Key Clinical and Histologic Features

Hallmarks:

• Gland formation: Acini, tubules, ducts lined by atypical epithelial cells.
• Mucin production: Intracellular or extracellular mucin (e.g., mucinous adenocarcinoma).
• Architectural disorder: Crowded glands, cribriform patterns, back‑to‑back glands, invasion into stroma.
• Grading: Based on gland formation, nuclear atypia, mitotic rate (e.g., Gleason for prostate adenocarcinoma).

Common sites and subtypes:

Site	Subtypes/Notes
Lung	Bronchioloalveolar (lepidic), mucinous, solid, papillary (8140/3).
Colorectum	Tubular, mucinous, signet‑ring, serrated (8140/3, 8480/3).
Pancreas	Ductal adenocarcinoma (8140/3, pancreatobiliary type).
Prostate	Acinar adenocarcinoma (Gleason grading).
Breast	Ductal (NOS), lobular, mucinous (8140/3, 8480/3, 8520/3).
Esophagus/Stomach	Intestinal‑type, diffuse (signet‑ring), Barrett’s‑related.

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Coding Context (ICD‑O‑3 / ICD‑10‑CM Notes)

Morphology codes (ICD‑O‑3):[2][1]

• 8140/3 - Adenocarcinoma, NOS (most common; used when subtype unspecified).
• 8480/3 - Mucinous adenocarcinoma.
• 8260/3 - Signet‑ring cell carcinoma (subtype of adenocarcinoma).
• 8255/3 - Adenocarcinoma with mixed subtypes.
• Behavior: /3 = malignant.[2]

ICD‑10‑CM: No standalone code; site‑specific (e.g.):

• C34.x - Malignant neoplasm of bronchus/lung (with adenocarcinoma histology).
• C18.x - Malignant neoplasm of colon.
• C25.3 - Malignant neoplasm of pancreatic duct.
• C50.x - Malignant neoplasm of breast.[5][3]

Coding tips:

• Pair histology (8140/3) with primary site code.
• For metastatic adenocarcinoma, use C77-C80 series + primary site if known.
• Carcinoma in situ variants: D05.x (breast), D01.x (GI tract).[5]

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Related Terms

Benign counterpart:

• adenoma (adenomatous polyp): Benign glandular tumor (/0 in ICD‑O); precursor to adenocarcinoma in colon, stomach.[2]

Other glandular malignancies:

• Cystadenocarcinoma: Cystic glandular cancer.
• Papillary adenocarcinoma: With papillary projections.
• Tubular adenocarcinoma: Predominantly tubular glands.

Precursors:

• dysplasia / adenoma / metaplasia (e.g., Barrett’s esophagus → esophageal adenocarcinoma).

Molecular markers:

• KRAS, EGFR, BRAF mutations (lung, colorectal); HER2 amplification (breast, gastric); MSI‑high (colorectal Lynch syndrome).[2]

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Clinical Details

Risk factors (site‑specific):

• Colorectal: Polyps, IBD, Lynch syndrome, diet.
• Lung: Smoking (especially adenocarcinoma in non‑smokers).
• Pancreas: Smoking, chronic pancreatitis, diabetes, BRCA2.
• Prostate: Age, family history, African ancestry.

Prognosis: Varies widely by site/stage (poor for pancreatic; better for early colorectal).

One‑Sentence Summary
Adenocarcinoma (8140/3), the most common epithelial malignancy, arises from glandular tissue across organs like lung (C34.x), colon (C18.x), and pancreas (C25.3), forming disorganized glands or mucin and often progressing from benign adenomas via dysplasia.

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DERIVATIONS of adenocarcinoma

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Med roots Appendix A Prefixes Appendix B Combining Forms Appendix C Suffixes Appendix D Suffix forms