# Situation: A 52-year-old woman has invasive ductal carcinoma of the left breast, stage IIB (T2 N1 M0), grade 3, estrogen receptor-positive and human epidermal growth factor receptor 2 (HER2)-negative. She undergoes a modified radical mastectomy with axillary lymph node dissection and will then receive doxorubicin and cyclophosphamide every 21 days. She has no known drug allergies. Invasive ductal carcinoma arises in the milk ducts of the breast. In the classification of tumors by tissue of origin, it belongs to which group?

> source: MyMerci (mymerci.kr)  
> url: https://mymerci.kr/pages/nclex_q.php?qn_id=629730  
> language: ko  
> subject: Nursing Practice III — Care of Clients with Problems in Surgery, Oxygenation, Fluid and Electrolytes, Infectious, Inflammatory and Immunologic Response, Cellular Aberrations

## 문제

Situation: A 52-year-old woman has invasive ductal carcinoma of the left breast, stage IIB (T2 N1 M0), grade 3, estrogen receptor-positive and human epidermal growth factor receptor 2 (HER2)-negative. She undergoes a modified radical mastectomy with axillary lymph node dissection and will then receive doxorubicin and cyclophosphamide every 21 days. She has no known drug allergies.

Invasive ductal carcinoma arises in the milk ducts of the breast. In the classification of tumors by tissue of origin, it belongs to which group?

## 보기

1. Transitional cell carcinoma
2. Squamous cell carcinoma
3. Adenocarcinoma **✔ 정답**
4. Sarcoma

**정답: 3**

## 해설

Tumors are named by their tissue of origin. The breast ducts are lined by glandular epithelium, and a malignant tumor of glandular epithelium is an adenocarcinoma, as in breast, colon, and prostate cancer. Squamous cell carcinoma arises from surface squamous epithelium, and sarcoma arises from connective tissue.

## 심화 해설

Tumor classification by tissue of origin

A malignant tumor is named according to the tissue from which it arises, not the organ where it happens to be found. Invasive ductal carcinoma begins in the epithelial cells lining the milk ducts of the breast. Because the ducts are lined by glandular epithelium, a cancer arising there is classified as an adenocarcinoma. The prefix adeno- refers to gland, and carcinoma indicates a malignancy of epithelial origin.

Breast, colon, prostate, and pancreatic cancers are all adenocarcinomas because they originate from glandular or ductal epithelial tissue. This is a high-yield distinction for licensure exams, because the same reasoning applies across multiple organ systems.

The provided abstract reinforces that ductal carcinomas arise from the terminal ducts of the mammary gland — specifically the terminal ductal structures of Lob 1, which are the sites of origin for ductal carcinomas [1]. These terminal ducts are lined by glandular epithelium, and their high proliferative activity and estrogen receptor content help explain both the origin and the hormone-responsive behavior of this tumor type [1]. For this patient, the tumor is estrogen receptor-positive, which is consistent with the biology of glandular epithelial cells in the breast [1].

| Classification | Tissue of origin | Examples |
| --- | --- | --- |
| Adenocarcinoma | Glandular or ductal epithelium | Breast, colon, prostate, pancreas |
| Squamous cell carcinoma | Surface squamous epithelium | Skin, esophagus, cervix, lung |
| Transitional cell carcinoma | Urothelium (transitional epithelium) | Bladder, ureter, renal pelvis |
| Sarcoma | Connective tissue (mesenchymal origin) | Bone (osteosarcoma), fat (liposarcoma), muscle (rhabdomyosarcoma) |

Watch out! The term invasive ductal carcinoma describes the anatomic location and growth pattern, but it does not change the histologic classification. Regardless of whether the tumor is ductal or lobular, breast cancers of epithelial origin are still adenocarcinomas.

Key point! Carcinoma always means epithelial origin; sarcoma always means connective tissue origin. If a stem asks about a tumor arising in glandular tissue, the answer is adenocarcinoma — even when the organ is the breast.References (research sources)

- [1]Breast development, hormones and cancer.Research articleRusso J, Russo IH (2008) · DOI: 10.1007/978-0-387-78818-0_4

## 임상 시나리오

Tumor Naming by Tissue of OriginAdenocarcinoma in breast cancer
Malignant tumors are named by the tissue of origin, not the organ. Invasive ductal carcinoma arises from glandular epithelium lining the milk ducts, making it an adenocarcinoma.

The same classification applies across organs: breast, colon, prostate, and pancreas cancers are adenocarcinomas because they originate from glandular or ductal epithelial tissue.

CautionDo not confuse with squamous cell carcinoma, which arises from surface squamous epithelium, or sarcoma, which arises from connective tissue.

## 핵심 개념

- **Adenocarcinoma** — Malignant tumor arising from glandular or ductal epithelium, such as breast, colon, or prostate cancer.
- **Carcinoma** — Malignant tumor of epithelial origin.
- **Sarcoma** — Malignant tumor arising from connective tissue, such as bone or muscle.
- **Invasive ductal carcinoma** — Breast cancer that begins in the milk duct lining and invades surrounding breast tissue.

## 같은 주제 문제

- [Situation: A 52-year-old woman has invasive ductal carcinoma of the left breast, stage IIB…](https://mymerci.kr/pages/nclex_q.php?qn_id=629731)
- [Situation: A 52-year-old woman has invasive ductal carcinoma of the left breast, stage IIB…](https://mymerci.kr/pages/nclex_q.php?qn_id=629732)
- [Situation: A 52-year-old woman has invasive ductal carcinoma of the left breast, stage IIB…](https://mymerci.kr/pages/nclex_q.php?qn_id=629733)
- [Situation: A 52-year-old woman has invasive ductal carcinoma of the left breast, stage IIB…](https://mymerci.kr/pages/nclex_q.php?qn_id=629734)
- [Situation: A 66-year-old man with adenocarcinoma of the lower rectum undergoes abdominoper…](https://mymerci.kr/pages/nclex_q.php?qn_id=629735)
- [Situation: A 66-year-old man with adenocarcinoma of the lower rectum undergoes abdominoper…](https://mymerci.kr/pages/nclex_q.php?qn_id=629736)
- [Situation: A 66-year-old man with adenocarcinoma of the lower rectum undergoes abdominoper…](https://mymerci.kr/pages/nclex_q.php?qn_id=629737)
- [Situation: A 48-year-old woman with stage IIB squamous cell carcinoma of the cervix is rec…](https://mymerci.kr/pages/nclex_q.php?qn_id=629738)

---

More free questions: [기출문제](https://mymerci.kr/)

_학습 참고용입니다. 실제 임상은 최신 지침과 소속 기관 프로토콜을 따르세요._