Джейсон Вассерман, доктор медицинских наук, FRCPC
16 апреля 2026
Муцинозная карцинома of the ovary is a type of ovarian cancer that develops from cells that produce mucus. Under the microscope, the tumor cells resemble the cells that line parts of the digestive tract, such as the stomach or intestines, which is why pathologists describe this tumor as having “mucinous” or gastrointestinal-type features. Mucinous carcinoma is relatively uncommon, accounting for about 3–4% of ovarian carcinomas. Most cases are diagnosed at an early stage and are still confined to the ovary at the time of detection. This article will help you understand the findings in your pathology report — what each term means and why it matters for your care.
Каковы симптомы?
Most patients develop symptoms related to a pelvic mass. These may include abdominal swelling or bloating, pelvic pressure, abdominal or pelvic pain, or a feeling of fullness. Because mucinous carcinomas can grow slowly and often reach a large size before causing symptoms, they are sometimes detected when imaging is performed for unrelated reasons. In many cases the tumor is very large at the time of diagnosis.
Что вызывает муцинозную карциному яичника?
The exact cause is not fully understood, but several genetic changes within tumor cells are known to play a role. Mutations in the KRAS gene — which normally helps regulate cell growth — are found in about two-thirds of cases and are thought to occur early in tumor development. Loss of the CDKN2A gene, which normally acts as a brake on cell division, is also found in about three-quarters of cases. Mutations in the TP53 gene, which controls cell growth and DNA repair, are present in roughly two-thirds of cases and appear to be associated with progression from a less aggressive tumor to invasive carcinoma. Amplification of the ERBB2 (HER2) gene, which drives cell growth signaling, is seen in approximately 15–25% of cases.
Связь с нераковыми опухолями яичников
Many mucinous carcinomas of the ovary develop from pre-existing noncancerous or граница ovarian tumors. In most cases, the cancer arises from a муцинозная пограничная опухоль — a tumor whose cells are abnormal but have not yet grown into the surrounding tissue. Over time, additional genetic changes can allow the tumor to become invasive. Less commonly, mucinous carcinoma arises from other доброкачественный ovarian tumors such as зрелые кистозные тератомы or Brenner tumors. When the pathologist examines the tumor under the microscope, it may contain a mixture of benign, borderline, and malignant areas side by side, which supports the idea that the carcinoma developed gradually from a pre-existing lesion.
Could a mucinous tumor in the ovary have come from another organ?
One of the most important questions in the evaluation of a mucinous ovarian tumor is whether it actually started in the ovary or whether it spread to the ovary from another organ. Cancers that begin in the appendix, colon, stomach, or pancreas can spread to the ovary and produce tumors that look almost identical to primary mucinous carcinoma of the ovary under the microscope — because they also produce mucus and contain intestinal-type cells.
Determining the site of origin is critical because the treatment and prognosis differ significantly depending on where the cancer started. Several features help the pathologist make this distinction. Primary mucinous carcinomas of the ovary tend to be unilateral (affecting only one ovary), are often very large (greater than 10–13 cm), and frequently show a mixture of benign, borderline, and malignant areas. Metastatic tumors from another organ are more likely to involve both ovaries, to be smaller, and to show a pattern of growth on the surface of the ovary or as separate nodules within the ovarian tissue rather than arising from within it.
For this reason, surgeons often remove the appendix during surgery for a mucinous ovarian tumor, even if it looks normal to the naked eye. The appendix is then examined under the microscope to look for a primary tumor that may have spread to the ovary. Additional immunohistochemistry tests are also used to help identify the site of origin.
Как ставится диагноз?
Диагноз обычно ставится после исследования образца ткани под микроскопом. патолог. The sample is most often obtained when the tumor is removed at surgery. If surgery is performed, the pathologist also examines other tissues removed during the operation — including the fallopian tubes, uterus, appendix, lymph nodes, and any abdominal tissue samples — to help determine where the tumor started and how far it has spread.
Under the microscope, mucinous carcinoma of the ovary shows cells that produce large amounts of mucus, forming glands that resemble those of the gastrointestinal tract. The tumor may contain a mixture of benign, borderline, and malignant areas within the same specimen. Two main patterns of вторжение can be seen, and identifying which pattern is present is important because it affects prognosis. In the expansile (confluent) pattern, the tumor glands are tightly crowded together, with very little supporting tissue between them, creating a labyrinth-like or maze-like appearance. This pattern is more common and associated with better outcomes. In the infiltrative (destructive) pattern, irregular glands, nests, or individual tumor cells push into the surrounding tissue and often cause a fibrous reaction called desmoplasia. This pattern is less common but is associated with a higher risk of spread and a worse prognosis.
To confirm the diagnosis and distinguish primary mucinous carcinoma of the ovary from a tumor that has spread from another organ, the pathologist uses иммуногистохимия (IHC) — a technique that uses antibodies to detect specific proteins in tumor cells. Most primary ovarian mucinous carcinomas stain strongly for CK7 and may also show variable staining for CK20, CEA, and CDX2, which are markers commonly expressed in gastrointestinal-type cells. Many tumors also stain for CA19-9. Markers that are typically negative include WT1, napsin A, estrogen receptor (ER), and progesterone receptor (PR), which help distinguish mucinous carcinoma from серозная карцинома высокой степени злокачественности и эндометриоидная карцинома of the ovary. A small subset of tumors shows focal PAX8 staining, which may support an ovarian origin. Metastatic colorectal or appendiceal cancers, by contrast, often show the reverse pattern: strong CK20 and CDX2 with weak or absent CK7.
Once the cancer is confirmed as a primary ovarian tumor, imaging — typically CT of the abdomen and pelvis — is used to assess the extent of disease and guide staging and treatment planning.
Гистологический класс
Mucinous carcinoma of the ovary is graded based on the FIGO (International Federation of Gynecology and Obstetrics) system, using the proportion of the tumor that grows as solid sheets of cells rather than as recognizable glands:
- FIGO 1-й класс (хорошо дифференцированный) — Less than 5% of the tumor grows as solid sheets. The tumor forms well-developed glands and tends to behave in a relatively predictable way.
- FIGO, 2 класс (умеренно дифференцированный уровень) — Between 6% and 50% of the tumor grows as solid sheets.
- Класс FIGO 3 (слабо дифференцированный) — More than 50% of the tumor grows as solid sheets. This is associated with more aggressive behavior and a higher risk of recurrence.
In addition to FIGO grade, the pattern of invasion — expansile versus infiltrative — is also an important prognostic factor specific to mucinous carcinoma. Tumors with infiltrative invasion behave more aggressively than those with expansile invasion, even at the same FIGO grade.
Распространение опухоли
The pathologist examines all tissue samples to determine whether the tumor has spread beyond the ovary. Tumor cells may involve nearby structures such as the fallopian tube, uterus, or other pelvic tissues. Tumor cells may also spread to the peritoneum (the thin lining of the abdominal cavity) or the omentum. Unlike most other types of ovarian carcinoma, the majority of mucinous carcinomas are confined to the ovary at the time of diagnosis. When spread beyond the ovary is found in a mucinous tumor, the possibility that it originated elsewhere in the body is considered carefully before concluding the spread represents true advanced-stage primary ovarian cancer.
Состояние капсулы яичника
The outer covering of the ovary is called the capsule. The pathologist will note whether the capsule is intact or ruptured, and whether tumor is present on the outer surface. These findings affect the stage:
- Капсула целая, опухоль на поверхности отсутствует. Suggests the cancer is still contained within the ovary, associated with an earlier stage and better prognosis.
- Разрыв капсулы или опухоль на поверхности — Даже если другие способы распространения не выявлены, разрыв капсулы или поражение поверхности усугубляют стадию заболевания.
- Разрыв во время операции — Если разрыв капсулы происходит во время операции, а не до нее, это отмечается отдельно и также влияет на стадирование заболевания.
Лимфоваскулярная инвазия
Лимфоваскулярная инвазия means that tumor cells have been found inside small blood vessels or lymphatic channels within the tissue. This finding suggests that tumor cells may have had an opportunity to travel to lymph nodes or distant organs, and it can influence staging and treatment decisions.
Лимфатический узел
Лимфатический узел are small, bean-shaped structures that help filter the body’s lymphatic fluid and support the immune system. In ovarian cancer surgery, lymph nodes from the pelvis and along the major abdominal blood vessels (para-aortic nodes) may be removed and examined. If tumor cells are found in the lymph nodes, the cancer is considered to have spread beyond the ovary and the stage increases. Lymph node spread is less common in mucinous carcinoma than in high-grade serous carcinoma, but it still occurs and must be assessed.
В заключении патологоанатомического исследования будет указано:
- Общее количество исследованных лимфатических узлов.
- Количество лимфатических узлов, содержащих опухолевые клетки.
- Размер самого крупного опухолевого очага.
- Местоположение всех пораженных лимфатических узлов (тазовые или парааортальные).
Метастазы в лимфатических узлах классифицируются по размеру. Изолированные опухолевые клетки (размером 0.2 мм или менее) регистрируются как pN0(i+) и не учитываются как окончательные метастазы во всех системах стадирования. Метастазы размером от 0.2 мм до 10 мм классифицируются как pN1a (небольшие метастазы), а метастазы размером более 10 мм — как pN1b (крупные метастазы). Эти различия в размерах влияют на стадию N.
Биомаркеры и молекулярные исследования
Biomarker testing in mucinous carcinoma of the ovary examines specific proteins and genetic changes in tumor cells that may help guide treatment decisions. The biomarker landscape for this tumor type differs from that of other ovarian carcinomas — in particular, BRCA and HRD testing are not routinely performed because mucinous carcinoma does not respond to PARP inhibitors the way high-grade serous carcinoma does. The most clinically important biomarker in this tumor type is HER2.
ГЕР2 (ЭРББ2)
HER2 is a protein found on the surface of some cancer cells that acts like a receiving antenna for growth signals, telling the cell to grow and divide. In a healthy cell, HER2 activity is tightly controlled. In some mucinous carcinomas of the ovary, the ERBB2 gene — which provides the instructions for making HER2 — is amplified, meaning extra copies of the gene are present. This leads to overproduction of HER2 protein, which drives uncontrolled cell growth. HER2 amplification is found in approximately 15–25% of mucinous ovarian carcinomas, making it the most important actionable biomarker in this tumor type.
HER2 testing follows a two-step process. First, immunohistochemistry (IHC) is performed to measure the amount of HER2 protein on the surface of tumor cells. Results are reported as 0, 1+, 2+, or 3+. A score of 3+ is considered positive, indicating high HER2 protein overexpression. A score of 0 or 1+ is negative. A score of 2+ is equivocal — meaning the result is borderline — and requires confirmatory testing by fluorescence in situ hybridization (FISH), which directly counts the number of HER2 gene copies in the tumor cells to determine whether the gene is amplified.
Patients with HER2-positive mucinous ovarian carcinoma may be eligible for HER2-targeted therapy. Agents such as trastuzumab (Herceptin) and trastuzumab-based combinations have shown activity in HER2-amplified mucinous ovarian carcinomas, particularly in advanced or recurrent disease. Your oncologist will advise whether HER2-targeted therapy is appropriate for your situation.
Белки репарации несоответствия (MMR)
Mismatch repair (MMR) proteins — MLH1, PMS2, MSH2, and MSH6 — work together to fix small copying errors that arise when cells divide. When one or more of these proteins is absent, errors accumulate and the tumor is described as mismatch repair–deficient (dMMR) or microsatellite instability–high (MSI-H). Mismatch repair deficiency is uncommon in mucinous carcinoma of the ovary, occurring in a minority of cases.
When present, dMMR has two important implications. First, dMMR/MSI-H tumors may be eligible for immunotherapy with pembrolizumab (Keytruda), which has pan-tumor approval for dMMR/MSI-H solid tumors that have progressed after prior treatment. Second, dMMR may indicate Lynch syndrome — an inherited condition caused by a germline mutation in one of the MMR genes that significantly raises the lifetime risk of ovarian, uterine, colorectal, and other cancers. When MMR deficiency is identified, referral to a genetic counsellor is recommended to assess for Lynch syndrome, as the implications extend to blood relatives who may not yet know they are at risk.
Testing is performed by immunohistochemistry on tumor tissue. Results are reported as retained expression (normal) or loss of expression (abnormal) for each of the four MMR proteins. When MLH1 and PMS2 are both lost, additional testing for a BRAF V600E mutation or MLH1 promoter methylation helps distinguish sporadic, non-inherited loss from Lynch syndrome.
КРАС
KRAS is a gene that acts like an on/off switch for cell growth signals. Normally, the KRAS protein turns on briefly in response to growth signals, then turns off again. A mutation in KRAS can lock the switch in the “on” position, causing the cell to grow and divide continuously without waiting for the normal signal. KRAS mutations are found in about two-thirds of mucinous ovarian carcinomas and are thought to be an early event in tumor development.
KRAS mutation results are reported as mutated or wild-type (normal). At present, there is no approved KRAS-targeted therapy specifically for mucinous ovarian carcinoma, although KRAS G12C inhibitors (such as sotorasib) have been approved for other cancer types and may be considered in some clinical settings. KRAS testing is increasingly performed as part of broader molecular profiling to characterize the tumor and identify any potentially targetable alterations.
ПД-Л1
PD-L1 is a protein that some tumor cells use to evade the immune system. Testing is performed by immunohistochemistry and is typically reported as a Combined Positive Score (CPS). In ovarian cancer, PD-L1 testing is most relevant in the setting of advanced or recurrent disease, where immunotherapy may be considered. The role of PD-L1 as a predictive marker, specifically in mucinous ovarian carcinoma, remains under investigation. Your oncologist will consider PD-L1 results alongside other clinical and molecular findings.
Для получения дополнительной информации о тестировании биомаркеров при раке яичников см. Биомаркеры и молекулярное тестирование .
Патологическая стадия (pTNM)
Стадирование описывает степень распространения рака. При раке яичников патологическая стадия определяется по системе AJCC TNM, которая тесно соответствует системе стадирования FIGO, используемой гинекологическими онкологами. Стадия состоит из трех компонентов: T (степень локального распространения опухоли), N (распространилась ли опухоль на лимфатические узлы) и M (распространилась ли опухоль на отдаленные органы). Стадия M определяется с помощью методов визуализации и обычно не указывается в патологическом заключении, если только во время операции не было взято исследование на отдаленные метастазы.
Стадия опухоли (pT)
- pT1 (FIGO Stage I) — Опухоль может поражать только один или оба яичника или фаллопиевы трубы.
- pT1a — Опухоль обнаружена только в одном яичнике или фаллопиевой трубе; капсула целая; опухолевые клетки в брюшной жидкости отсутствуют.
- pT1b — Опухоль поражает оба яичника или фаллопиевы трубы; капсулы неповреждены; в брюшной жидкости опухолевые клетки отсутствуют.
- pT1c — Опухоль ограничена яичником/маточной трубой, но сопровождается разрывом капсулы, наличием опухолевых клеток на внешней поверхности или обнаружением раковых клеток в брюшной жидкости или смывах.
- pT2 (стадия FIGO II) — Опухоль распространилась за пределы яичников или маточных труб в область таза.
- pT2a — Распространение на матку, другую фаллопиеву трубу или другой яичник.
- pT2b — Распространение на другие ткани таза, такие как мочевой пузырь или прямая кишка.
- pT3 (стадия III по классификации FIGO) — Опухоль распространилась за пределы таза в брюшину или регионарные лимфатические узлы.
- pT3a — Микроскопическое распространение на брюшину за пределами таза, с поражением или без поражения региональных лимфатических узлов.
- pT3b — Видимые опухолевые очаги размером до 2 см на брюшине за пределами таза, с поражением лимфатических узлов или без него.
- pT3c — Видимые опухолевые очаги размером более 2 см за пределами таза или распространение на наружную поверхность (капсулу) печени или селезенки, с поражением лимфатических узлов или без него.
Примечание: Распространение внутри ткани печени или селезенки (а не только на их поверхности) классифицируется как М1 (стадия IVB).
Узловая стадия (pN)
- pN0 — В региональных лимфатических узлах раковых клеток не обнаружено.
- pN0(i+) — В лимфатических узлах обнаруживаются только отдельные опухолевые клетки (0.2 мм или менее); во всех системах стадирования они не считаются метастазами.
- pN1 — Раковые клетки присутствуют в региональных лимфатических узлах.
- pN1a — Опухолевые отложения размером до 10 мм.
- pN1b — Опухолевые отложения размером более 10 мм.
Каков прогноз?
прогноз for mucinous carcinoma of the ovary depends primarily on the stage at diagnosis and the pattern of invasion. Because the majority of cases are diagnosed at stage I — confined to one ovary — overall survival is more favorable than for high-grade serous carcinoma. However, advanced-stage mucinous ovarian carcinoma is difficult to treat because this tumor type responds poorly to the standard platinum-based chemotherapy that works well for serous carcinoma.
Примерные показатели пятилетней выживаемости составляют:
- Этап I — 85–95%. Most patients with mucinous ovarian carcinoma are diagnosed at this stage, and outcomes are excellent with surgery alone in many cases.
- Этап II — 55-65%.
- Этап III — 20–35%. Advanced-stage mucinous carcinoma has a significantly worse prognosis than advanced-stage serous carcinoma because it is less responsive to standard chemotherapy.
- Четвертая стадия — Менее 15%.
Помимо стадии заболевания, на прогноз влияют следующие факторы:
- Pattern of invasion — Tumors with infiltrative (destructive) invasion behave more aggressively and have a worse prognosis than those with expansile (confluent) invasion, even when confined to the ovary.
- Гистологическая степень — Higher-grade tumors (grade 3) are associated with a greater risk of recurrence.
- Unilateral vs. bilateral involvement — A tumor confined to one ovary is associated with a better prognosis. Bilateral involvement raises the possibility of metastatic disease from another organ, which carries a different prognosis.
- Статус HER2 — HER2-positive tumors may respond to targeted therapy, which is an emerging treatment option in advanced disease.
- Статус капсулы — Capsule rupture before or during surgery increases the stage and is associated with a higher risk of recurrence.
Что происходит после постановки диагноза?
Treatment is planned by a multidisciplinary team that typically includes a gynecologic oncologist, medical oncologist, pathologist, and radiologist. The approach depends on the stage, invasion pattern, and biomarker results.
Surgery is the cornerstone of treatment. For most patients, this involves removal of the affected ovary and fallopian tube (and the contralateral ovary and uterus in most postmenopausal patients), the omentum, and the appendix. The appendix is routinely removed both to rule out an appendiceal primary tumor and because the appendix is a common site of origin for mucinous tumors that spread to the ovary. For early-stage, low-grade tumors with expansile invasion confined to one ovary, surgery alone may be sufficient, and fertility-sparing surgery may be possible in younger patients after careful discussion.
For patients with higher-stage disease or infiltrative invasion, chemotherapy is typically recommended after surgery. However, standard platinum-based chemotherapy (carboplatin and paclitaxel) is less effective in mucinous ovarian carcinoma than in serous carcinoma. For this reason, alternative chemotherapy regimens modeled on gastrointestinal cancers — such as FOLFOX or XELOX (oxaliplatin-based regimens) — are used in some cases, reflecting the gastrointestinal-like biology of mucinous ovarian carcinoma.
In patients with HER2-positive advanced or recurrent mucinous carcinoma, HER2-targeted therapy with trastuzumab or trastuzumab-based combinations may be considered. This is an area of active clinical investigation. Patients whose tumors show mismatch repair deficiency may be eligible for immunotherapy with pembrolizumab. Your oncologist will discuss which treatment approach is most appropriate for your specific situation.
Follow-up after treatment typically involves regular clinical assessments and monitoring with CA-125 (and CA19-9 in some cases), with imaging performed when there are signs of potential recurrence.
Вопросы к врачу
- Has my tumor been confirmed as a primary mucinous carcinoma of the ovary, and was the appendix examined to rule out an appendiceal primary?
- На какой стадии находится мой рак яичников, и что это означает для моего лечения и прогноза?
- Does my tumor show expansile or infiltrative invasion, and how does that affect my prognosis?
- What is the histologic grade of my tumor?
- Была ли капсула яичника целой, или она разорвалась до или во время операции?
- Was HER2 testing performed, and is my tumor HER2-positive?
- If my tumor is HER2-positive, am I eligible for HER2-targeted therapy?
- Было ли проведено тестирование системы репарации ошибок спаривания, и были ли потеряны какие-либо белки MMR?
- Если будет обнаружен дефицит MMR, нужно ли мне проходить обследование на синдром Линча, и следует ли обследовать членов моей семьи?
- What chemotherapy regimen do you recommend, given that mucinous carcinoma responds differently to treatment than other ovarian cancers?
- Какой график последующих визитов вы рекомендуете после завершения лечения?
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