Concurrent malignant phyllodes tumor and invasive ductal carcinoma in a young female: a rare case report

Abstract

Introduction:

Phyllodes tumors are rare fibroepithelial breast neoplasms, typically affecting middle-aged women. Malignant phyllodes tumors (MPTs) account for a minority of these cases and are extremely uncommon in adolescents. The synchronous presentation of MPT with contralateral invasive ductal carcinoma (IDC) is exceptionally rare and presents unique diagnostic and therapeutic challenges.

Case presentation:

We report the case of a 19-year-old female who presented with a rapidly enlarging mass in the left breast, initially misdiagnosed as an abscess. On physical examination, a distinct right breast mass and bilateral axillary lymphadenopathy were also noted. Imaging and biopsy revealed an MPT in the left breast. Histopathology confirmed IDC in the right breast and metastatic adenocarcinoma in both axillae. Immunohistochemistry revealed high proliferative activity in the IDC. The patient underwent left mastectomy and was started on systemic chemotherapy, with a favorable initial response.

Clinical discussion:

This case underscores the importance of considering rare malignancies in adolescents with atypical breast presentations and highlights the diagnostic limitations of imaging alone. The concurrent diagnosis of two distinct breast cancers in a young patient raises concern for a possible underlying genetic predisposition and supports the need for a multidisciplinary approach to management.

Conclusion:

The simultaneous occurrence of MPT and IDC in adolescents is extraordinarily rare. Early histopathological assessment, comprehensive bilateral evaluation, and coordinated oncologic care are essential for optimal management in such complex cases.

Introduction

Phyllodes tumors are rare fibroepithelial neoplasms of the breast, characterized by the proliferation of both stromal and epithelial components^[1,2]. They represent less than 1% of all breast tumors and typically present in women around the median age of 45 years. In a cohort of 2935 women with breast lesions in Southern Punjab, Pakistan, phyllodes tumors were identified in only 12 cases, underscoring their rarity in the regional population^[3]. Based on histopathological features such as stromal cellularity, atypia, mitotic rate, and tumor margins, the World Health Organization classifies phyllodes tumors into benign, borderline, and malignant subtypes^[4,5].

HIGHLIGHTS

• Rare case of malignant phyllodes tumor with contralateral breast cancer.

• One of the few synchronous dual breast cancers reported in an adolescent.

• Abscess-like presentation highlights diagnostic pitfalls in young patients.

• Early biopsy and bilateral evaluation are crucial in adolescent breast tumors.

Although phyllodes tumors may clinically and radiologically resemble fibroadenomas, malignant variants (MPTs) demonstrate aggressive behavior, including rapid growth, local recurrence, and, less commonly, distant metastasis^[6]. Diagnosis often relies on core needle biopsy, although definitive classification may not be possible until surgical excision and full histological evaluation are performed^[7,8].

The presentation of MPTs in adolescents is extremely rare, and their coexistence with other primary breast malignancies is even more uncommon. Invasive ductal carcinoma, the most frequent type of breast cancer, typically affects older women and is rarely seen concurrently with phyllodes tumors. The synchronous occurrence of MPT and invasive ductal carcinoma in opposite breasts has only been described in isolated case reports^[9,10].

We report the case of a 19-year-old female diagnosed with a malignant phyllodes tumor in the left breast and synchronous invasive ductal carcinoma in the right breast, with metastatic involvement of bilateral axillary lymph nodes. This case highlights a highly unusual dual malignancy in an adolescent, presenting significant diagnostic, pathological, and therapeutic challenges that warrant multidisciplinary attention and consideration of possible genetic etiology.

This case report has been written according to SCARE guidelines^[11].

Case presentation

A 19-year-old female presented to our clinic with rapidly enlarging left-sided breast swelling, which subsequently progressed to involve the right breast along with swelling in the right supraclavicular and axillary lymph nodes. Her medical history was notable for a left breast abscess that had not resolved with antibiotics. Her family history was significant for breast carcinoma, as her mother had previously been diagnosed with the disease. The family history was further reviewed for additional risk factors, but no other hereditary cancer syndromes were identified.

On physical examination, the patient was alert and hemodynamically stable. The left breast mass was firm, lobulated, painless, and mobile, without overlying skin changes or nipple discharge. The right breast also contained palpable lumps, and enlarged right supraclavicular and axillary lymph nodes were noted. A distinct, lobulated mass was palpable in the right axilla.

Previous interventions revealed extensive debris-filled collections across all quadrants of the left breast, with thickened, hypervascular septations, sparing the upper quadrant. Necrotic lymph nodes were identified in the left axilla. Surgical incision and drainage were performed to evacuate necrotic material. Following this, the left breast initially regressed but then rapidly regrew. During laparoscopic drainage of the new mass, no pus was found, raising suspicion for a neoplasm.

CBC showed a total leukocyte count of 7.32 × 10³/µL (normal range), RBC 4.74 × 10⁶/µL with hemoglobin 10.9 g/dL and hematocrit 33.1%, indicating mild microcytic hypochromic anemia (Mean Corpuscular Volume (MCV) 70 fL, Mean Corpuscular Hemoglobin (MCH) 23 pg). Platelet count was slightly raised at 458 × 10³/µL. Differential leukocyte count revealed neutrophils 59.3%, lymphocytes 24.1%, monocytes 12.6%, eosinophils 2.9%, and basophils 0%. Overall, the findings are consistent with mild anemia with borderline thrombocytosis, relative neutrophilia, lymphopenia, and monocytosis, which may reflect the inflammatory and immune alterations commonly associated with breast malignancy. Histopathological analysis of the left breast biopsy revealed a malignant phyllodes tumor with immunohistochemistry positive for CK and P63, positive in epithelial and myoepithelial cells, respectively. Tumor architecture showed a hypercellular malignant neoplasm composed of spindle cells with stromal overgrowth. Individual cells showed pleomorphic, vesicular nuclei with inconspicuous nucleoli and scattered mitosis (differentiating MPT from borderline tumor) (Fig. 1). A contrast-free chest CT scan showed large, necrotic, lobulated masses in both breasts, along with enlarged right axillary and supraclavicular lymph nodes (Fig. 2).

Figure 1.

Histopathology of synchronous left malignant phyllodes tumor and right invasive ductal carcinoma with bilateral axillary nodal metastases (H&E). (A) Malignant phyllodes tumor in the left breast: epithelial-lined clefts imparting a leaf-like architecture with markedly hypercellular stroma (arrows). H&E, ×40. (B) Stromal component in left breast: densely cellular spindle-cell proliferation with nuclear pleomorphism and conspicuous mitotic activity (asterisk), consistent with malignant stroma. H&E, ×40. (C) Invasive ductal carcinoma with squamoid differentiation in the right breast: infiltrative nests/cords of atypical epithelial cells within a desmoplastic stroma; focal squamoid features (arrows). H&E, ×10. (D) Axillary lymph node: metastatic carcinoma effacing nodal architecture; cohesive sheets of malignant epithelial cells with a high nuclear-to-cytoplasmic ratio (arrow) and background hemorrhage (arrowhead). H&E, ×40. Metastatic carcinoma was present in nodes from both axillae; (D) shows a representative node.

Figure 2.

Bilateral breast malignancy with nodal involvement on contrast-enhanced CT. Axial contrast-enhanced CT images of the chest show lobulated, heterogeneously enhancing masses in both breasts (yellow arrows). There is associated overlying cutaneous thickening consistent with inflammatory/tumoral involvement (green arrow). Enlarged axillary lymph nodes are presented bilaterally, bulkier on the right (red arrows).

A Tru-Cut core biopsy of the right breast confirmed grade 3 invasive ductal carcinoma with squamoid differentiation on H&E, and immunohistochemistry showed ER-negative, PR-negative, and HER2-negative status with a Ki-67 index of 50%–60% indicating high proliferative activity. Fine-needle aspiration cytology of bilateral axillary lymph nodes revealed metastatic adenocarcinoma (Fig. 3). In view of the positive family history of breast carcinoma, genetic counseling was done; however, genetic testing (BRCA1/2 and TP53) along with other relevant tumor markers could not be performed due to financial constraints.

Figure 3.

Right-breast carcinoma: Ultrasonographic and immunohistochemical findings. (A, B) Targeted high-resolution breast ultrasonography (B-mode; color Doppler performed) demonstrates an irregular, ill-defined, heterogeneous hypoechoic mass (31.4 × 20.5 mm) at the 11–12 o’clock position of the right breast (red arrows), with overall assessment BI-RADS 5. Concomitant axillary ultrasound showed multiple rounded lymph nodes with cortical thickening and loss of the fatty hilum. (C, D) Immunohistochemistry for cytokeratin AE1/AE3 shows diffuse membranous staining in ≥95% of tumor cells, confirming epithelial differentiation (original magnification, ×40).

The patient underwent a left mastectomy; right mastectomy and axillary dissection were deferred at the time. The patient initially received three cycles of the FAC chemotherapy regimen comprising 5-Fluorouracil, Doxorubicin, and Cyclophosphamide. The tumor showed a good clinical response with notable regression; chemotherapy-induced vomiting was also observed. This was followed by three additional cycles of the same regimen, after which disease progression was noted. Follow-up contrast CT chest showed an ill-defined heterogeneously enhancing mass lesion in the right breast with underlying pectoral muscle thickening and another ill-defined heterogeneously enhancing mass in the left breast associated with underlying pectoral muscle thickening, and overlying skin thickening and retraction, along with bilateral auxiliary lymphadenopathy. Follow-up Color Doppler USG showed an ill-defined, irregular, heterogeneous mass measuring 31.4 × 20.5 mm seen at 11–12 o’clock position in the right breast parenchyma with multiple well-defined, rounded lymph nodes noted in the right axilla with loss of fatty hilum, BI-RADS 5. On radiological investigations, no suspicious lesion or evidence of metastatic disease was observed. Chemotherapy was subsequently switched to carboplatin and paclitaxel for three cycles. The patient has now completed these three cycles with a favorable response and is currently planned for surgery following completion of chemotherapy.

Discussion

The coexistence of malignant phyllodes tumor and invasive ductal carcinoma in contralateral breasts is an exceptionally rare clinical entity, particularly in adolescents^[5,12]. The simultaneous presentation in a 19-year-old underscores the diagnostic and therapeutic complexities involved and raises the possibility of underlying genetic predispositions.

Phyllodes tumors are rare fibroepithelial neoplasms, comprising approximately 0.3%–0.5% of all breast tumors^[13,14]. Among these, malignant subtypes account for about 6.5%–27% of cases, underscoring the clinical importance of malignant phyllodes tumors despite their rarity^[15–19]. The tumor is biphasic and composed of epithelial and stromal components, with the stromal component determining the tumor’s biological behavior^[20]. MPTs are characterized by rapid growth and a high risk of local recurrence. Although metastasis typically occurs via the hematogenous route (most commonly to the lungs), rare cases of lymphatic involvement have also been reported^[6,21].

Our case is a unique report in the diagnosis and management of breast cancer, sharing several similarities with previously reported cases while also demonstrating important distinguishing features. Like other cases, our patient had a family history of breast carcinoma and presented with a palpable breast mass. However, unlike other cases, it initially mimicked an abscess, a potential diagnostic pitfall in young women with rapidly enlarging breast masses^[22]. Despite a history of abscess drainage and antibiotic therapy, the mass regrew, prompting further imaging and biopsy. Histopathological analysis confirmed the diagnosis of MPT with immunopositivity for CK and P63, consistent with stromal overgrowth and atypia. Concurrently, a right-sided breast mass and bilateral axillary lymphadenopathy were investigated and revealed high-grade invasive ductal carcinoma with squamous differentiation and a Ki-67 index of 50%–60%, indicating high proliferative activity. The coexistence of these two distinct histological subtypes raises important clinical questions. MPTs are primarily managed through surgical excision with clear margins to minimize recurrence risk. In contrast, invasive ductal carcinoma often necessitates a multimodal treatment strategy, incorporating surgery, systemic chemotherapy, and lymph node evaluation^[20,23]. Lactate dehydrogenase (LDH) is an important enzyme in cancer diagnosis and monitoring, with the advantage of being easily measurable in standard lab settings^[24]. LDH release is an indicator of cell membrane damage, which not only allows the loss of LDH but also of the components of the secretory killing pathway, resulting in natural killer cell dysfunction with the progression of disease^[25]. In our patient, a left mastectomy was performed, and chemotherapy was initiated, resulting in a favorable response. The decision to delay the right mastectomy and axillary dissection was made in the context of the patient’s condition and multidisciplinary planning.

In previous literature, very few cases of phyllodes tumor in adolescents have been reported, and all have been treated with wide local excision of the breast. Prihantono et al^[26] presented the case where the patient of phyllodes tumor offered wide excision with a resection margin of 1 cm, followed by the McKissock procedure. Makar et al^[6] presented a similar case treated with a wide breast excision with complex closure of a 10 cm wound, followed by re-excision lumpectomy to ensure full 1 cm margins around the malignant tumor.

Bilateral axillary lymph node metastases from separate primary tumors present a diagnostic and management challenge. While axillary dissection is not typically indicated for phyllodes tumors, nodal involvement may necessitate a departure from standard protocols^[27]. It is crucial in such cases to distinguish between stromal and epithelial metastasis using histology and immunohistochemistry. Given the patient’s young age and dual malignancy, an inherited genetic predisposition, such as a BRCA1/2 or TP53 mutation, should be considered^[28]. About 25% of inherited breast cancer cases are linked to mutations in rare but high-risk genes like BRCA1, BRCA2, and others, which can increase breast cancer risk by up to 80% over a lifetime. Additionally, mutations in moderate-risk genes, such as CHEK2 and ATM, account for around 2%–3% of cases, roughly doubling the risk of breast cancer^[29]. Although not explored in this case due to financial constraints, genetic counseling and testing could provide valuable insights into both disease pathogenesis and long-term surveillance strategies.

This case emphasizes the importance of maintaining a high index of suspicion in young women presenting with rapidly enlarging breast masses, particularly when clinical progression does not follow the typical course of benign lesions. It also highlights the necessity of bilateral evaluation and early histopathological confirmation to avoid diagnostic delays and initiate timely treatment. Multidisciplinary care is essential in managing such complex presentations, involving surgical oncology, pathology, radiology, and potentially genetic counseling.

Ethical approval

Ethical approval is not required for the case report in our institution, Nishtar Medical University.

Consent

Written informed consent was obtained from the patient for the publication of this case report and accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal on request.

Sources of funding

Not applicable.

Author contributions

A.M.J., N.M., M.S.K., Z.A., A.A.R., and A.K. conceptualized the study, curated data, and conducted the investigation. A.M.J., N.M., M.S.K., and Z.A. wrote the original manuscript. A.A.R., A.K., and M.A. reviewed and edited the manuscript. A.K. and A.A.R. administered the project. M.A. and A.K. supervised the study.

Conflicts of interest disclosure

The authors declare no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Research registration unique identifying number (UIN)

Not applicable.

Guarantor

Mohamed Antar.

Data availability statement

All the relevant data have been included in the manuscript itself.

Peer and provenance statement

Not invited.