Giant uterine tumor and miscarriage: how to proceed?

Expanding uterine masses can be the cause of pregnancy loss and add technical difficulties to uterus evacuation due to the intense anatomical distortion of the endocervical canal and uterine cavity. The literature is scarce in the peculiarities of the management of missed abortions in uterus with important distorted anatomies. We report a case of a primigravida patient who presented a rapid and expressive increase of abdominal volume due to a giant uterine mass, evolving to miscarriage. Ultrasound can be a useful tool, allowing visualization of the endocervical path and uterine cavity, helping to perform uterine evacuation in the presence of anatomical distortion without compromising the reproductive future. To the best of our knowledge, no such case has been previously reported.

Impact of Pregnancy on Breast Cancer Features and Prognosis.

BACKGROUND: pregnancy-associated breast cancer (PABC) affects one in 3000 pregnancies, often presenting with aggressive features. METHODS: We retrospectively evaluated a cohort of 282 young BC patients (≤45 years old) treated between 1995 and 2019, dividing them into three groups: nulliparous women, women with PABC (diagnosed within 2 years since last pregnancy) and women with BC diagnosed > 2 years since last pregnancy. This last group was further stratified according to the time between pregnancy and BC. The analysis encompassed histological factors (tumor size, histotype, grading, nodal involvement, multifocality, lympho-vascular invasion, hormone receptor expression, Ki-67 index, and HER2 expression), type of surgery and recurrence. RESULTS: Age at diagnosis was younger in nulliparous than in parous women (p < 0.001). No significant differences were noticed regarding histological characteristics and recurrences. At univariate analysis, nodal involvement (OR = 2.4; p < 0.0001), high tumor grade (OR = 2.6; p = 0.01), and lympho-vascular invasion (OR = 2.3; p < 0.05), but not pregnancy (OR = 0.8; p = 0.30), influenced DFS negatively. Multivariate analysis confirmed nodal involvement as the only negative independent prognostic factor for a worse DFS (OR = 2.4; p = 0.0001). CONCLUSIONS: in our experience, pregnancy is not an independent adverse prognostic factor for BC DFS.

Navigating an unexpected diagnosis - experience of a tertiary referral centre with two cases of intraplacental choriocarcinoma.

Intraplacental choriocarcinoma is a rare tumour, with approximately 62 reported cases. It may manifest as a spectrum of disease ranging from an incidental lesion diagnosed on routine placental examination to disseminated maternal and/or neonatal disease. In this case series, we presented two rare cases of intraplacental choriocarcinoma with extremely varied clinical presentations. The extremely varied clinical presentations of both patients described in the case series complicated the process of arriving at the diagnosis. In both cases, subsequent investigations showed no maternal or neonatal metastasis, and maternal serum beta-hCG levels downtrended with conservative management. We aim to highlight the importance of performing a detailed physical examination and evaluation of the patient and multidisciplinary management with oncology opinion. A detailed examination of the placenta should also be considered when faced with obstetric complications so that early diagnosis and the required management can be executed in a prompt fashion.

Malignant tumour in pregnancy: Ewing-like sarcoma of the gluteal region.

We report a case of an Ewing-like sarcoma of the gluteal region with ongoing growth during the second trimester of pregnancy and noted during the third trimester. This lesion was consequently studied to infer its malignant potential. Several examinations were conducted to characterise this lesion, such as ultrasound and MR, which showed signs of tumourous invasion of the deep tissues of the gluteal region.Given that the pregnancy was at the end of the third trimester, the decision was made to schedule the delivery at 37 weeks of gestation and treat the tumour afterwards to balance maternal and fetal health.This case illustrates the need for a detailed investigation and guidance by a multidisciplinary team to provide prenatal counselling regarding a malignant tumour during pregnancy.

Worse histopathology and prognosis in women with breast cancer diagnosed during the second trimester of pregnancy.

BACKGROUND: Evidence suggests that women with breast cancer diagnosed during pregnancy (PrBC) and within 2 years of delivery (PPBC) have similar survival compared to women diagnosed not near pregnancy if adjusted for stage and subtype. To investigate whether this is true for all subtypes and for both pregnancy and post-delivery periods, we examined clinicopathologic features and survival in women with breast cancer by trimesters and 6-month post-delivery intervals. MATERIALS AND METHODS: Women diagnosed with invasive breast cancer during 1992-2018 at ages 18-44 years were identified in the Swedish Cancer Register, with information on childbirths from the Swedish Multi-Generation Register and clinical data from Breast Cancer Quality Registers. Each woman with PrBC or PPBC was matched 1 : 2 by age and year to comparators diagnosed with breast cancer not near pregnancy. Distributions of stage, grade, and surrogate subtypes were compared. Adjusted hazard ratios (HRs) with 95% confidence intervals (CIs) for breast cancer mortality were estimated using Cox regression. RESULTS: We identified 1430 women with PrBC and PPBC (181 during pregnancy, 499 during the first and 750 during the second year after delivery). Compared to 2860 comparators, women with PrBC and PPBC in the first year after delivery had a significantly higher proportion of luminal human epidermal growth factor receptor 2 (HER2)-positive, HER2-positive and triple-negative tumours, and more advanced stage at diagnosis. After adjustment for age, year, parity, country of birth, hospital region, subtype, and stage, women diagnosed during the second trimester had a worse prognosis than matched comparators (HR 1.8, 95% CI: 1.0-3.2). CONCLUSIONS: Women diagnosed during pregnancy or within the first year after delivery have a worse prognosis than women diagnosed not near pregnancy due to adverse tumour biology and advanced stage at diagnosis. A worse prognosis for women diagnosed during the second trimester remained after multivariable adjustment, possibly reflecting difficulties to provide optimal treatment during ongoing pregnancy.

First Reported Histologically and Molecularly Confirmed Bilateral High-Grade Serous Ovarian Adenocarcinoma Metastasized to Placental Decidua of the Membranes.

A 43-year-old female presented with blood loss and persistent abdominal pain at 14 weeks of gestation. Ultrasound examination and subsequent magnetic resonance imaging (MRI) revealed bilateral multicystic uterine adnexa. Exploratory laparotomy was performed at 17 weeks of gestation and bilateral serous ovarian adenocarcinoma FIGO stage IIIC was diagnosed. Complete cytoreductive surgery (CRS) was not feasible at that moment. Nine days after the exploratory laparotomy, immature rupture of membranes and contractions occurred and she delivered a premature boy after 19 weeks of gestation. Pathological examination of the placenta revealed that her ovarian cancer metastasized to the membranes. We describe the first case of ovarian cancer metastasized to the decidua of the placental membranes with histological, immunohistochemical, and molecular confirmation. This case highlights the importance of conscientious evaluation of placenta and membranes in pregnant women with ovarian cancer.

Gynecological cancer during pregnancy-From a gyne-oncological perspective.

Gynecological cancer diagnosed during pregnancy requires accurate diagnosis and staging to determine optimal treatment based on gestational age. Cervical and ovarian cancers are the most common and multidisciplinary team collaboration is pivotal. Magnetic resonance imaging and ultrasound can be used without causing fetal harm. In cervical cancer, early-stage treatments can often be delayed until fetal lung maturation and cesarean section is recommended if disease prevails, in combination with a simple/radical hysterectomy and lymphadenectomy. Chemoradiotherapy, the recommended treatment for advanced stages, is not compatible with pregnancy preservation. Most gestational ovarian cancers are diagnosed at an early stage and consist of nonepithelial cancers or borderline tumors. Removal of the affected adnexa during pregnancy is often necessary for diagnosis, though staging can be performed after delivery. In selected cases of advanced cervical and ovarian cancers, neoadjuvant chemotherapy may be an option to allow gestational advancement but only after thorough multidisciplinary discussions and counseling.

Pregnancy-related breast cancer: 14-year experience in a tertiary institution in Hong Kong.

BACKGROUND: The incidence of pregnancy-associated breast cancer (PABC) is increasing. Its tumor characteristics and overall survival compared with those in nonpregnant patients remain controversial. While there have been suggestions that PABC patients have a 40 % increase in the risk of death compared to non-pregnant patients, other studies suggested similar disease outcomes. This study aims to review our local experience with PABC. METHODS: Twenty-eight patients diagnosed with PABC and twenty-eight patients diagnosed at premenopausal age randomly selected by a computer-generated system during the same period were recruited. Background characteristics, tumor features, and survival were compared. RESULTS: Among the twenty-eight pregnant patients, seventeen were diagnosed during pregnancy, and eleven were diagnosed in the postpartum period. Compared to the non-pregnant breast cancer patients, they presented with less progesterone receptor-positive tumor (35.7 % vs. 64.2 %, p = 0.03). Although there was no statistically significant difference in tumor size (p = 0.44) and nodal status (p = 0.16), the tumor tended to be larger in size (2.94 +/- 1.82 vs 2.40 +/- 1.69 cm) and with more nodal involvement (35.7 % vs 25.0 %). There was also a trend of delayed presentation to medical attention, with a mean duration of 13.1 weeks in the PABC group and 8.6 weeks in the control group. However, the overall survival did not differ (p = 0.63). CONCLUSION: PABC is increasing in incidence. They tend to have more aggressive features, but overall survival remains similar. A multidisciplinary approach is beneficial for providing the most appropriate care.

Prognostic and reproductive outcomes in women who had uterine myomas removed during cesarean section and sutured using different techniques.

BACKGROUND: In this study, the prognostic and reproductive outcomes of women who underwent excision of uterine myomas and were sutured using different techniques while undergoing a cesarean section were investigated. METHODS: A total of 299 females who underwent cesarean section between January 2015 and June 2022 due to a scarred uterus were enrolled in this study. These participants were segregated into two categories: the experimental group (comprising 155 cases) in which uterine myoma (single lesion) was excised during the cesarean procedure, and the control group (consisting of 144 cases) in which only the cesarean section was conducted. A comparison between the two groups was carried out based on the following parameters: volume of intraoperative bleeding (mL), additional measures taken for intraoperative hemostasis (n, %), percentage (%) of patients experiencing postoperative fever, duration required for the passage of gas (hours [h]), length of hospital stay (days [d]), weight of newborns (kg) and their Apgar scores, and the reproductive outcomes of the experimental group assessed two years after the surgical procedure. RESULTS: In the experimental group, the amount of bleeding during surgery, occurrence of postoperative fever among women, time taken for patients to resume passing gas, and length of hospital stay were 540.65 ± 269.12 mL, 9.03%, 15.99 ± 4.68 h, and 5.08 ± 1.18 days, respectively. In contrast, the control group had values of 409.03 ± 93.24 mL, 2.77%, 16.24 ± 4.92, and 4.47 ± 0.70 days, respectively (P < 0.05). No notable increase was observed in the need for additional intraoperative hemostasis measures, and there was no significant difference in the time it took for patients to pass gas after the surgery. All newborns had positive health status. In the experimental group, 25 patients underwent subsequent pregnancies, and 15 of them successfully reached full-term deliveries, all of which had positive outcomes. CONCLUSION: Combining myomectomy with various suture methods during cesarean delivery did not cause excessive bleeding and resulted in healthy newborns. This approach offers the advantage of avoiding additional surgeries under anesthesia and can be considered a viable option. Subsequent pregnancies after myomectomy were considered high-risk.

A long-term retrospective analysis of management of cervical cancer during pregnancy.

OBJECTIVE: This study aims to describe cervical cancer during pregnancy (CCP) and investigate factors associated with survival outcomes. METHODS: This retrospective matched study included CCP patients from May 2007 to August 2021 and matched non-pregnant cervical cancer patients (1:2) based on age (±5 years), year at diagnosis (±2 years), histological type and stage (2018 FIGO). The Kaplan-Meier method and multivariate Cox regression analyses were used to assess the impact of pregnancy and clinicopathologic factors on prognosis. RESULTS: Thirty-eight CCP patients (stage IA to IIIC) and 76 non-pregnant patients were included. Most CCP patients were diagnosed in the first (31.6%) or second (47.4%) trimester. CCP patients had a longer waiting time than non-pregnant patients. Pregnancy continued in 42.1% (continuation of pregnancy [COP] group) and was terminated in 57.9% (termination of pregnancy [TOP] group) of patients. Survival analysis showed no significant differences in recurrence-free survival (RFS) or overall survival (OS) between pregnant and non-pregnant patients or between the COP and TOP groups. At the end of the follow-up period (range 12-178 months), 23 children born to CCP patients exhibited normal development. CONCLUSION: Pregnancy does not impact cervical cancer prognosis. The oncologic outcomes of the TOP and COP groups were comparable. A pregnancy-preserving strategy could be considered for managing CCP patients.

Retrospective analysis of 26 cases of pregnancy luteoma.

BACKGROUND: Pregnancy luteoma is a rare hormone-dependent ovarian tumor-like lesion caused by increased androgenic activity during pregnancy. OBJECTIVE: To explore the clinical history, ultrasound manifestations, and differential diagnosis of pregnancy luteoma. METHOD: A retrospective analysis was conducted on 26 cases of pregnancy luteoma diagnosed by postoperative pathology, from 2009 to 2022. All cases were from two hospitals: Shanghai First Maternity and Infant Hospital and International Peace Maternity and Child Health Hospital. The clinical history data and ultrasound characteristics were analyzed and the relevant literature was reviewed. RESULTS: Among the 26 cases, five of them had preoperative ultrasound images. Among these five cases, three patients showed hyperechoic masses with less internal uniformity, while two demonstrated loculated anechoic zones, with clear boundary and regular morphology. Color Doppler showed no obvious internal blood flow signals, or that blood flow signals were visible within the cyst wall and hyperechoic mass. Among the cases, 16 had multiple gestations, while two visited the clinic due to sudden abdominal pain and a huge ovarian mass was found by ultrasonography. The ovarian lump was detected during routine obstetric ultrasound in three cases. The remaining were ovarian cysts found incidentally during caesarean section. Four patients presented with hairy manifestations and one patient had a deepened voice. CONCLUSION: There is no characteristic ultrasound of pregnancy luteoma, and its diagnosis is mainly based on clinical history data and laboratory tests.

[Deforming endonasal mass during pregnancy]. / Deformierende endonasale Raumforderung während der Schwangerschaft.

This article presents the case of a 33-year-old woman who consulted the authors' ENT clinic in the 39th week of pregnancy with recurrent epistaxis. A livid endonasal mass was found on the left side, subtotally displacing the nose and leading to deformation of the external nose. External biopsy provided no indications of malignancy. Postpartum CT of the paranasal sinuses revealed a mass destroying the cartilaginous nasal septum. Endoscopic resection of the finding was performed with preservation of the clinically sound nasal septal cartilage. Histopathological examination revealed a capillary hemangioma, which was classified as granuloma gravidarum due to its occurrence during pregnancy.

Successful Pregnancy in a 29-Year-Old G3P2 Shortly After Unilateral Pneumonectomy and Systemic Chemotherapy for Lung Cancer: A Case Report.

BACKGROUND The incidence of tumors during pregnancy, generally, is very uncommon. The incidence of lung cancer during pregnancy, specifically, is exceedingly rare. Several investigations have documented favorable maternal-fetal outcomes for later pregnancies after pneumonectomy due to non-cancer-related causes (mostly progressive pulmonary tuberculosis). However, very little is known about maternal-fetal outcomes for future conceptions after pneumonectomy due to cancer-related causes and subsequent chemotherapy cycles. This is an important knowledge gap in the literature that needs to be filled. CASE REPORT A 29-year-old woman (non-smoker) had adenocarcinoma of the left lung, which was discovered during her pregnancy at 28 weeks of gestation. She underwent an urgent lower-segment transverse cesarean section at 30 weeks and subsequently underwent unilateral pneumonectomy and then completed her planned adjuvant chemotherapy. The patient was incidentally found to be pregnant at 11 weeks of gestation (roughly 5 months after the completion of her adjuvant chemotherapy cycles). Hence, the conception was estimated to have happened roughly 2 months after the completion of her chemotherapy cycles. A multidisciplinary team was formed and it was decided to keep her pregnancy as there was no clear medical reason to terminate it. The pregnancy was carried out to term gestation at 37+4 weeks with close monitoring, and she delivered a healthy baby via lower-segment transverse cesarean section. CONCLUSIONS Successful pregnancy after unilateral pneumonectomy and adjuvant systematic chemotherapy is rarely reported. The maternal-fetal outcomes after unilateral pneumonectomy and systematic chemotherapy need expertise and a multidisciplinary approach to prevent complications.

Pregnancy-associated breast cancer: does timing of presentation affect outcome?

PURPOSE: Pregnancy-associated breast cancer (PABC) comprises breast cancer diagnosed during the gestational period or within 12 months postpartum. While the incidence of PABC appears to be increasing, data regarding prognosis remain limited. METHODS: Here we evaluate clinicopathologic features, treatments, and clinical outcomes among women with stage 0-III PABC diagnosed between 1992 and 2020. Comparisons were made between women who were diagnosed with PABC during gestation and those who were diagnosed within 12 months postpartum. RESULTS: A total of 341 women were identified, with a median age of 36 years (range 25-46). The pregnancy group comprised 119 (35%) women, while 222 (65%) women made up the postpartum group. Clinicopathologic features were similar between groups, with most patients being parous and presenting with stage I and II disease. Treatment delays were uncommon, with a median time from histologic diagnosis to treatment of 4 weeks for both groups. Recurrence-free survival was similar between groups: 67% at 10 years for both. While 10-year overall survival appeared higher in the postpartum group (83% versus 78%, p = 0.02), only the presence of nodal metastases was associated with an increased risk of death (hazard ratio 5.61, 95% CI 2.20-14.3, p < 0.001), whereas timing of diagnosis and receptor profile did not reach statistical significance. CONCLUSION: Clinicopathologic features of women with PABC are similar regardless of timing of diagnosis. While 10-year recurrence-free survival is similar between groups, 10-year overall survival is higher among women diagnosed postpartum; however, timing of diagnosis may not be the driving factor in determining survival outcomes.

Pregnancy-associated breast cancer: a multicenter study comparing clinicopathological factors, diagnosis and treatment outcomes with non-pregnant patients.

PURPOSE: Pregnancy-associated breast cancer (PABC), defined as breast carcinoma diagnosed during pregnancy or in the first post-partum year, is one of the most common gestation-related malignancies with reported differences in tumor characteristics and outcomes. This multicenter study aims to review cases of PABC in Singapore, including their clinicopathological features, treatment, and clinical outcomes compared to non-PABC patients. METHODS: Demographic, histopathologic and clinical outcomes of 93 PABC patients obtained from our database were compared to 1424 non-PABC patients. RESULTS: PABC patients presented at a younger age. They had higher tumor and nodal stages, higher tumor grade, were more likely to be hormone receptor negative and had a higher incidence of multicentric and multifocal tumors. Histological examination after definitive surgery showed no significant difference in tumor size and number of positive lymph nodes suggesting similar neoadjuvant treatment effects. Despite this, PABC patients had worse outcomes with poorer overall survival and disease-free survival, OS (P < 0.0001) and DFS (P < 0.0001). Termination of pregnancy did not improve survival. CONCLUSION: Patients with PABC present at a higher stage with more aggressive disease and have poorer outcomes compared to non-PABC patients. Reducing delay in diagnosis and treatment may help improve survival.

Characterization and clinical management of abnormal cytology findings in pregnant women: a retrospective analysis.

PURPOSE: The diagnosis of cervical intraepithelial neoplasia during pregnancy poses a great challenge to the treating clinician and the patient. According to the current guidelines, watchful waiting during pregnancy can be justified. Only in cases of invasion, immediate treatment may be indicated. However, few data are available on the management of cervical dysplasia during pregnancy. Further research is important for counselling affected women. METHODS: Data of pregnant patients with suspected cervical dysplasia who presented to the University Women's Hospital Tübingen between 2008 and 2018 were evaluated retrospectively. Colposcopic, cytologic, and histologic assessment was performed for diagnosis. Data on remission, persistence and progression of disease based on histologic and cytologic assessment and the mode of delivery were correlated. RESULTS: 142 patients were enrolled. Cytology at first presentation was PAPIII (-p/-g) in 7.0%, PAPIIID (IIID1/IIID2) in 38.7%, PAPIVa (-p/-g) in 50.0%, PAPIVb (-p) in 2.8%, and PAPV (-p) in 1.4%. All cases with suspected invasion were recorded at the initial presentation. Complete histological or cytological remission was observed in 24.4%, partial remission in 10.4%, persistence in 56.3%, and progression in 8.9%. In two cases (1.5%) progression to squamous cell carcinoma occurred. CONCLUSIONS: Watchful waiting for cervical intraepithelial neoplasia during pregnancy seems to be sufficient and oncologically safe. It is important to exclude invasion during pregnancy, to perform frequent colposcopic, cytologic and histologic examinations and to ensure a postpartum follow-up examination to initiate the treatment of high-grade lesions. Spontaneous delivery seems to be safe in patients with cervical dysplasia, Caesarean section is not indicated.

Breast Cancer during Pregnancy as a Special Type of Early-Onset Breast Cancer: Analysis of the Tumor Immune Microenvironment and Risk Profiles.

Breast cancer during pregnancy (PrBC) is a rare tumor with only a little information on its immune landscape. Here, we sought to characterize the cellular composition of the tumor microenvironment (TME) of PrBC and identify its differences from early-onset breast cancer (EOBC) in non-pregnant women. A total of 83 PrBC and 89 EOBC were selected from our Institutional registry and subjected to tumor-infiltrating lymphocytes (TILs) profiling and immunohistochemistry for CD4, CD8, forkhead box P3 (FOXP3), and programmed death-ligand 1 (PD-L1) (clone 22C3). A significantly lower frequency of hormone receptor (HR)-positive tumors was observed in PrBC. The prevalence of low/null PD-L1 and CD8+TILs was higher in PrBC than in the controls, specifically in HR+/HER2- breast cancers. PrBC had a significantly higher risk of relapse and disease-related death, compared to EOBC. The presence of TILs and each TIL subpopulation were significantly associated with disease relapse. Moreover, the death rate was higher in PrBC with CD8+ TILs. The TME of PrBC is characterized by specific patterns of TIL subpopulations with significant biological and prognostic roles. Routine assessment of TILs and TILs subtyping in these patients would be a valid addition to the pathology report that might help identify clinically relevant subsets of women with PrBC.

Personalized treatment of malignant tumors during pregnancy.

The combination of pregnancy and cancer is a challenge for the patient and a problematic clinical dilemma for the doctor. In this retrospective observational cohort study, we have tried to analyze our experience in the management of such patients. This review includes 41 patients with malignant neoplasms detected during pregnancy who received treatment at the Almazov National Medical Research Centre from 2015-2021. The majority of patients received treatment during pregnancy (n=26, 63.4%): chemotherapy - 19 (46.3%) (in 2 cases in combination with surgery), surgical treatment - 7 (17, 1%) patients. In most cases, delivery was at term (n=28, 68.3%). All children born at term were mature and had no growth restriction, regardless of whether the mothers received treatment during pregnancy or not. When detecting cancer during pregnancy, an immediate follow-up examination is required to assess the extent of the tumor and current fetal state. If pregnancy prolongation is requested, the treatment should not be postponed, except for systemic chemotherapy in the first trimester of pregnancy, pelvic radiation at any term.

Does mode of delivery impact the course of cervical dysplasia in pregnancy? A review of 219 cases.

OBJECTIVE: The prevalence of cervical intraepithelial neoplasia (CIN) in pregnancy is about 1%. The aim of this study was to analyze the regression, persistence and progression rates of cervical dysplasia in pregnancy and the impact of delivery mode. STUDY DESIGN: In this retrospective study, data from pregnant patients with abnormal cytology findings, who presented to a colposcopic outpatient clinic of a university hospital within the last 10 years, were analyzed. Information on cytology, histology and Human Papillomavirus (HPV) status during pregnancy and postpartum and mode of delivery was collected. RESULTS: 219 women, who were assessed with cytology and /or biopsy antepartum and postpartum between January 2010 and July 2020, were included in the study. Antepartum patients presented with low grade squamous intraepithelial lesions (LSIL) in 37% and high grade squamous intraepithelial lesions (HSIL) in 53%. During pregnancy biopsy was performed in 78 patients (36%). Postpartum evaluation revealed an overall regression rate of 39%. Persistence rates were especially high in the HSIL group with 70 %. HSIL regressed in 28 %. Progression to invasive disease was rare and seen in two patients postpartum only. 141 women delivered vaginally (VD) and 51 received a cesarean section (CS). Regression rates were similar: 36 % and 47 %. There was no significant difference in progression or persistence rates. CONCLUSION: Our study demonstrates that mode of delivery does not influence the course of SIL. SIL show high rates of regression and persistence, progression to invasive disease is rare.

[A Case of Pregnancy-Associated Breast Cancer Which Underwent Surgical Treatment during Pregnancy and Chemotherapy after Delivery].

CASE: A 37-year-old pregnant woman arrived at our hospital with an abnormal mammogram. MEDICAL HISTORY: Mammography performed in June 2018 revealed an abnormal shadow on the left breast. Cytology from the 6-mm tumor in the left upper-outer quadrant revealed a malignancy. At the same time, a transvaginal echo revealed cysts, and the patient was diagnosed at 5 weeks gestation. Needle biopsy revealed a luminal A-like cStage Ⅰ, cT1bN0M0 invasive ductal carcinoma (IDC). Tumor resection and sentinel lymph node biopsy were performed under local anesthesia at 12 weeks gestation, and post-delivery adjuvant therapy was planned. Histologic examination of the resected tumor revealed that it was HER2-positive( immunohistochemistry score 3+); therefore, we had to reconsider the use of trastuzumab and decided to administer it to the patient after childbirth. The patient gave birth by cesarean section, and weekly paclitaxel plus trastuzumab was initiated 7 months after surgery. The patient is currently alive without recurrence. DISCUSSION: We faced several difficulties during the treatment of this patient. Postoperative adjuvant therapy is recommended to be administered 8 weeks after the surgical resection of the tumor. However, in our case, given that the tumor was HER2-positive, we could administer adjuvant therapy with trastuzumab only after delivery. Although the prevalence of breast cancer in women below the age of 40 years in Japan is currently as low as 4-6%, the incidence of pregnancy-associated breast cancer is predicted to increase as the number of elderly primigravida increases due to later marriage.