Journal of Advanced Clinical and Research Insights

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Missed diagnosis of phyllodes tumor and its implications: A case report
Missed diagnosis of phyllodes tumor and its implications:
A case report
K. R. Chatura, Jyothi Sajjan, C. R. Preethi
Dr. Chatura KR, Department of Pathology, J.J.M. Medical College, Davangere - 577 004, Karnataka, India.
Correspondence: Dr. Chatura KR, Department of Pathology, J.J.M. Medical College, Davangere - 577 004, Karnataka, India.E-mail:
Received 11 November 2017;
Accepted 28 December 2017
doi: 10.15713/ins.jcri.193
Phyllodes tumor, a fibroepithelial neoplasm, is rare and accounts for < 1% of breast tumors. It is often underdiagnosed by the pathologists and undertreated by the surgeons. The pathologist has a definite role in the pre-operative diagnosis of phyllodes which is essential for planning of surgery. A consistent differentiation of phyllodes tumor from cellular fibroadenoma is often difficult. Pre-operative diagnosis by fine-needle aspiration cytology or core needle biopsy is very important to avoid reoperation because of inadequate excision or to prevent unwarranted surgery. Its heterogeneity makes phyllodes tumor, a challenge for the pathologist and the clinician. We present the case of 45-year-old female with clinical differential diagnoses of phyllodes tumor or carcinoma of right breast lump. The lack of correlation between clinical and cytological diagnosis warranted a core biopsy which was not helpful. Intraoperative frozen section was requested on the subsequent lumpectomy. Grossly, a multicystic lesion with fronds projecting into them and cysts with mucinous material was seen. Cellular imprint smears and frozen and routine histopathology sections confirmed the diagnosis of phyllodes tumor. This case aptly describes the saga of a missed pre-operative diagnosis of phyllodes tumor.
Keywords:Core needle biopsy,fine-needle aspiration cytology,frozen section,phyllodes tumor
How to cite this article: Chatura KR. Missed diagnosis ofphyllodes tumor and its implications: A case report. J Adv ClinRes Insights 2018;5:3-5.


Phyllodes tumors of the breast are an uncommon, yet interesting group of fibroepithelial neoplasms that have a morphological resemblance at the benign end to the intracanalicular fibroadenoma albeit with increased stromal cellularity and leaf-like architecture.[1] They account for < 1% of all breast tumors.[2] The proposed World Health Organization classification of phyllodes tumor into benign, borderline, and malignant is based on a combination of histologic features, such as cellularity of stroma, nuclear atypia, mitosis, overgrowth of stroma, and infiltrative or pushing tumor margin.[3] The common argument in phyllodes tumor is pathologists'hesitate to diagnose it and surgeons do incomplete treatment. Hence, a diagnosis of phyllodes tumor before surgery is needed for planning the treatment. The phyllodes tumor has to be identified from the common benign fibroadenoma, which is its nemesis and a clinical, radiological, and morphological mimicker.[4]

A correct surgical planning with wide local excision and at least 1 cm margin is the needed treatment to avoid relook operation in cases of phyllodes.[5]

The triple assessment is the desired approach for breast lumps, which combines the results of clinical examination, radiological imaging, fine-needle aspiration cytology (FNAC), and/or core needle biopsy, to ensure diagnostic accuracy in breast disease before surgery. The efficacy of these components on their own and in combination remains poor for the diagnosis as phyllodes tumor features overlap with benign disease in all three categories.[2] Frozen section is useful to know the status of the margin intraoperatively because inadequate margins are often the cause for high recurrence associated with phyllodes.

Case Report

A 45-year-old female came to the surgical outpatient in our hospital with the complaint of lump in the right breast of 5-month duration and increasing in size during the past 2 months. Local examination of the right breast revealed an irregular nodular lump measuring 10 cm × 8 cm × 8 cm, firm and freely mobile occupying the entire breast with an overlying stretched skin. There was no axillary lymphadenopathy. She was clinicallydiagnosed to have carcinoma or phyllodes tumor of the rightbreast, and FNAC was advised.

Journal of Advanced Clinical & Research Insights, January-February, Vol 5, 2018 3

Chatura, et al. Phyllodes tumor on FNAC, core biopsy, and frozen section

FNAC of right breast mass was performed under asepticprecautions. Smears showed benign epithelial cells arrangedin cohesive clusters with few foamy macrophages and blood[Figure 1a]. No malignant cells were seen. FNAC was reportedas negative for malignancy with possibility of fibrocysticdisease. The lack of correlation between clinical and cytologicaldiagnosis warranted a core biopsy. The patient underwent coreneedle biopsy of the lump, fragments of which showed few ductssurrounded by hyalinized stroma, mildly cellular loose texturedstroma, and adipocytes [Figure 1b]. Cytological features werereported as negative for malignancy.

Due to inconclusive report on both FNAC and core needlebiopsy, the patient underwent lumpectomy and intraoperativefrozen section analysis for a diagnosis and tumor margins.

Gross findings

The mass measured grossly 10 cm × 8 cm × 8 cm. On cut surface,it was variegated with solid frond-like areas and numerous cysticspaces filled with mucin [Figure 1c]. Areas of hemorrhage andnecrosis were absent. Imprint smears were made and werestained with Hematoxylin and Eosin (H and E), Giemsa, andPapanicolaou stain. Representative areas were sampled for frozensection. Remaining tissue was fixed in formalin and processed forroutine paraffin-embedded sections.

Microscopic findings

Imprint smears were stained with Giemsa, H and E, andPapanicolaou stain. Smears revealed hypercellular stromalfragments and scattered benign appearing spindle cells with fewepithelial sheets in honeycomb pattern [Figure 1d].

Microscopy from frozen sections showed a tumor composedof leaf-like fronds lined by epithelium and cellular stroma ofspindle cells with areas of edema and hyalinization [Figure 1e].Occassional mitosis was seen. Diagnosis of benign phyllodestumor was rendered.

Routine histological examination showed biphasic tumorgrowth composed of two components, a bland epithelial partthat formed glandular structures and variable stroma fromhypercellularity to myxoid to hyalinized areas. Stromal cellswere round-to-oval cells that showed minimal degree ofpleomorphism and mitosis ranged from 3 to 5/10 high-powerfields (HPF). The final diagnosis was borderline phyllodestumor of the right breast [Figure 1f].


Phyllodes tumors of breast comprising of both stromal andepithelial elements are rare tumors. The phyllodes tumor wasdescribed by Johannes Muller, who named it as cystosarcomaphyllodes because of the tumor's fleshy appearance and tendencyto contain cystic spaces. This term is, however, a misnomer asthey are usually benign.

Classically, phyllodes tumor presents as a painless firmmobile, well-delineated lobulated mass. The mammographic orultrasonography features are not specific for phyllodes.[5] Hence,early diagnosis of phyllodes tumor is crucial so that it is possibleto be removed with adequate margin.

Pre-operative probable diagnosis can be achieved by FNACor core biopsy. The FNAC has limited success of around 12%in establishing a pre-operative diagnosis, limitation factorbeing the common cytological features with fibroadenoma.[6]Both the tumors have a dimorphic pattern with epithelial andstromal components. However, for the diagnosis of benignphyllodes tumor, at least two large stromal fragments whichare hypercellular and moderate-to-large number of dissociatedstromal cells are essential.[7] Core biopsy is preferred forestablishing the diagnosis before the surgical treatment.

An adequate and representative sample determines theaccuracy of FNAC. The hypercellular fragments may be missingbecause of the heterogeneous nature and if sampled fromrelatively hypocellular, myxoid, or hyalinized areas of stroma.FNAC has a high false-negative rate and only 63% overallaccuracy.[6]

In our case, cytology smears on FNAC showed no stromalfragments and the cellularity was limited to epithelial cells insheets. Failure of diagnosing phyllodes tumor on FNAC couldbe due to aspiration from cystic non-representative areas whichwere evident in the resected specimen.

Missed diagnosis of phyllodes tumor and its implications: A case report
Figure 1: (a) Smears showed benign epithelial cells arranged incohesive clusters with multinucleated foamy macrophage (Giemsa×40). (b) Core biopsy shows fragments with few ducts surroundedby hyalinized stroma and mildly cellular loose textured stromaHematoxylin and Eosin (H and E ×40). (c) Cut surface of freshlumpectomy specimen for frozen was variegated with solid frondlikeareas and cystic spaces filled with mucin. (d) Imprint smearsrevealed hypercellular stromal fragments and scattered benignappearing spindle cells (H and E ×40).(e) Frozen section showedleaf-like fronds lined by epithelium and cellular stroma of spindlecells (H and E ×40). (f) Hypercellular stromal overgrowth of spindlecells in borderline phyllodes (H and E ×40)

4 Journal of Advanced Clinical & Research Insights, January-February, Vol 5, 2018

Chatura, et al. Phyllodes tumor on FNAC, core biopsy, and frozen section

In our case, core biopsy showed epithelial and stromalcomponents with mild cellularity lacking mitosis, nuclear atypia,and stromal overgrowth. The absence of more representativeareas from a heterogenus tumor detered a more definite opinion.

Intraoperative examination remains a diagnostic methodwhen the mammographic screening, FNAC, and core needlebiopsy fail to make a preoperative diagnosis. In our case, dueto inconclusive report on both FNAC and core needle biopsyand high clinical suspicion of phyllodes tumor or malignancy,lumpectomy was done and intraoperative frozen sectionrequested for. On sampling, the mass and H and E stainedsmears showed a tumor composed of leaf-like fronds lined byepithelium and cellular stroma of spindle cells with a minimaldegree of pleomorphism and mitosis ranged from 3 to 5/10HPF. Final diagnosis rendered was a borderline phyllodes tumorof the right breast. The patient underwent simple mastectomyand on regular follow-up has not had recurrence to date.

Histopathologically, phyllodes tumors are classified asbenign, borderline, and malignant tumor based on features suchas tumor margin (pushing vs. infiltrative), degree of stromalovergrowth, stromal cellularity, tumor necrosis, pleomorphism,and the number of mitosis per HPF.[8] A benign tumor has 0-4mitosis/10 HPF, predominantly pushing margins with no ormild stromal atypia. Borderline tumors are identified by 5-9mitosis/10 HPF, pushing or infiltrative margin, and moderatestromal atypia. Malignant phyllodes are characterized by 10 ormore mitosis/10 HPF, predominantly infiltrating margins withhigh-grade stromal atypia.[6] In our case, features of borderlinephyllodes tumor were noted on resected lump.

Surgery is the treatment of choice for benign phyllodeswith wide local excision allowing 1-2 cm of clear margins in alldirections. Mastectomy is performed in malignant phyllodestumor and in tumors larger than 5 cm. The role of radiotherapyand chemotherapy is not certain.[9]


The role of cytology is inconclusive in phyllodes tumorsometimes as in this case. Early and correct diagnosis of thistumor is needed because of different treatment modalities.Pathologists can provide a more useful guidance to cliniciansif they attempt to differentiate between various fibroepitheliallesions.

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  9. Hassouna JB, Damak T, Gamoudi A, Chargui R, Khomsi F,Mahjoub S, et al. Phyllodes tumors of the breast: A case series of106 patients. Am J Surg 2006;192:141-47.

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