Infiltrative solid papillary carcinoma of the breast with axillary lymph node metastasis: a case report.

BACKGROUND: Solid papillary carcinoma (SPC) is a rare breast papillary tumor variant. The main histological features of SPC consist of neoplastic cell-rich nodules with thin fibrovascular cores, often accompanied by mucous secretion and neuroendocrine differentiation. Infiltrative solid papillary carcinoma (ISPC) tumor cells have an invasive, map-like growth pattern with serrated irregular growth. Due to its unique clinicopathological features, SPC is classified as two pathological tissue types based on the 2019 WHO classification of breast tumors: SPC in situ and ISPC. CASE PRESENTATION: We report a case of a 55-year-old female patient who was admitted to the hospital due to a painless left breast mass that had persisted for two years. Mammography suggested a mass in the left upper outer quadrant (BI-RADS 4B), and ultrasound of the breast demonstrated a cystic mass of the left breast (US_BI_RADS 4 C) with multiple enlarged lymph nodes in the left axilla. Postoperative pathology revealed ISPC with one lymph node metastasis in the left breast. Modified radical mastectomy was performed on the left breast. Subsequently, the patient received letrozole endocrine therapy, epirubicin hydrochloride and cyclophosphamide chemotherapy, and radiotherapy of the left chest wall and left upper and lower clavicular regions. After 17 months of follow-up, there was no evidence of recurrence or distant metastasis. CONCLUSIONS: SPC is a group of heterogeneous tumors. SPC in situ has a good prognosis. In contrast, ISPC has a unique histological morphology and growth pattern with invasive biological behavior that can lead to lymph node and distant metastases.

Intraductal papilloma with atypical ductal hyperplasia and neuroendocrine differentiation as a possible precursor lesion of solid papillary carcinoma.

Breast papillary neoplasms include a wide range of tumor types, and their pathological diagnosis is sometimes difficult. Furthermore, the etiology of these lesions is still not fully understood. We report the case of a 72-years-old woman referred to our hospital with bloody discharge from the right nipple. An imaging study detected a cystic lesion, including a solid component contiguous with the mammary duct, in the subareolar region. The lesion was then removed by segmental mastectomy. Pathological examination of the resected specimen revealed an intraductal papilloma with atypical ductal hyperplasia. Moreover, the atypical ductal epithelial cells expressed neuroendocrine markers. The presence of an intraductal papillary lesion with neuroendocrine differentiation suggests solid papillary carcinoma. Thus, this case suggests that intraductal papilloma could be a precursor of solid papillary carcinoma.

Papillary lesions of the breast - review and practical issues.

Papillary lesions of the breast represent a heterogeneous group of neoplasm featuring fibrovascular cores covered by epithelial cells with or without intervening myoepithelial cells. According to the World Health Organization classification of breast tumors, papillary lesions of the breast are further classified into intraductal papilloma (including intraductal papilloma with atypical ductal hyperplasia /ductal carcinoma in situ), papillary ductal carcinoma in situ, encapsulated papillary carcinoma, solid papillary carcinoma (in situ and invasive) and invasive papillary carcinoma. The overlapping morphological features and immunohistochemical profiles make accurate diagnosis of breast papillary lesion a challenge for pathologists. In this review, the morphological and relevant immunohistochemical features of papillary lesions are discussed, with further emphasis on some commonly encountered practical diagnostic issues. A simple diagnostic algorithm will be established. The relevant molecular characteristics will be discussed as well.

Solid Papillary Carcinoma and Encapsulated Papillary Carcinoma of the Breast: Clinical-Pathologic Features and Basement Membrane Studies of 50 Cases.

INTRODUCTION: Solid papillary carcinoma (SPC) and encapsulated papillary carcinoma (EPC) of the breast are usually considered in situ lesions due to favorable prognosis, despite the variable presence of myoepithelial cells. We aimed to describe clinical-pathologic features including basement membrane (BM) studies in these tumors. METHODS: Patients diagnosed with SPC and EPC in 2000-2019 were retrospectively identified. Microscopic slides and clinical history were reviewed. Immunohistochemical stains for BM and myoepithelial markers were performed. RESULTS: Of 23 SPCs and 27 EPCs, there were 5/23 (21.7%) pure SPCs and 9/27 (33.3%) pure EPCs, while 4/23 (17.4%) and 12/27 (44.5%) were associated with ductal carcinoma in situ (DCIS), and 6/23 (26.1%) and 6/27 (22.2%) with invasive carcinoma, respectively; 8/23 (34.8%) SPCs were considered invasive. The median tumor size was 1.7 cm (range 0.1-16). All tumors were positive for hormone receptors and negative for HER2. Myoepithelial cells were absent in 20 tumors (40%) and focally present in 30 (60%). Collagen IV and laminin were negative in most invasive lesions, but they were expressed in 21/21 (100%) and 18/21 (85.7%) of EPCs without invasion, and 16/17 (94.1%) and 10/17 (58.8%) SPCs, including invasive SPCs, respectively. Lymph node involvement was identified in 3/26 (11.5%) patients, including micrometastasis in 1 EPC associated with DCIS, macrometastasis in 1 EPC associated with invasive carcinoma, and isolated tumor cells in 1 invasive SPC. Of 31 patients with outcome data (median follow-up 35 months, range 1-85), 2 (6.5%; 1 SPC, 1 EPC) developed local recurrence, both associated with invasive carcinoma. No distant recurrences or deaths were observed. CONCLUSIONS: Our study confirms favorable prognosis of SPCs and EPCs, with 2 local recurrences occurring in the presence of invasion. SPCs are more commonly associated with invasive carcinoma or considered invasive compared to EPCs (60.9 vs. 22.2%). The presence of BM material and lack of lymph node involvement in most cases indicates that the majority of these tumors may represent in situ lesions; however, some may behave as low-grade invasive malignancy with metastatic potential even in the absence of conventional invasion.

INSM1 immunostaining in solid papillary carcinoma of the breast.

Solid papillary carcinoma (SPC) is a histological subtype of breast carcinomas. At least 50% of SPC show neuroendocrine differentiation. Insulinoma-associated protein 1 (INSM1) is a transcription factor now employed as a useful neuroendocrine marker. It is suppressed by the Notch signaling pathway in other neuroendocrine tumors. However, the usefulness of INSM1 as a neuroendocrine marker and the relationships between INSM1 and NOTCH receptors in SPC of the breast currently remain unclear. To clarify the usefulness of INSM1 as a neuroendocrine marker and the relationships between INSM1 and NOTCH receptors in SPC, we performed immunohistochemistry using 19 tissue specimens of SPC of the breast. We complementarily analyzed public RNA sequencing data on breast carcinomas. Immunohistochemical examinations revealed that the staining intensity of INSM1 was significantly higher in the neuroendocrine group than in the non-neuroendocrine group. Positive correlations were observed between INSM1 and synaptophysin (SYP), or chromogranin-A (CHGA). In all cases, NOTCH 2 and 3 were positive, while NOTCH 1 and 4 were negative. According to public RNA data analyses, there were positive correlations between INSM1 and SYP, or CHGA, and negative correlations between INSM1 and NOTCH1-3. INSM1 is useful as a diagnostic marker for SPC with neuroendocrine differentiation in the breast.

Tall cell carcinoma with reversed polarity: A case report of a very rare breast tumor entity and mini-review.

Tall cell carcinoma with reversed polarity (TCCRP) is a very rare variant of carcinoma of the breast, resembling the tall cell variant of papillary thyroid carcinoma, first described in 2003, recently recognized as a separate entity in the 5th edition of the WHO (World Health Organization) Blue Book Classification of breast tumors with alternative terminology of tall cell variant of papillary breast carcinoma and solid papillary carcinoma with reversed polarity. Here, we report an additional case of this rare tumor in a 71-year-old woman, and the problems correlating with its diagnosis.

A review of mucinous lesions of the breast.

Mucinous lesions of the breast include a variety of benign and malignant epithelial processes that display intracytoplasmic or extracellular mucin, including mucocele-like lesions, mucinous carcinoma, solid papillary carcinoma, and other rare subtypes of mucin-producing carcinoma. The finding of free-floating or stromal mucin accumulations is a diagnostic challenge of which the significance depends on the clinical, radiologic, and pathologic context. This article emphasizes the differential diagnosis between benign and malignant mucin-producing lesions, with a brief consideration of potential mimics, such as biphasic and mesenchymal lesions with associated with mucinous, myxoid, or matrix material.

Invasive lobular carcinoma with papillary features: A newly described variant that poses a difficult histologic differential diagnosis.

Recently, a new variant of ILC with papillary architecture has been described, which may mimic solid and encapsulated papillary carcinomas of the breast. We report the fifth case of ILC with a solid papillary-like growth pattern, which was initially misdiagnosed as an encapsulated papillary carcinoma. Subtle discohesion in the tumor cells, coupled with the presence of classic invasive lobular carcinoma infiltrating beyond the capsule of the papillary tumor, prompted evaluation with E-cadherin, confirming the diagnosis. We review the histologic differential diagnosis and stress the importance of correct classification to ensure appropriate management for patients.

Solid papillary carcinoma of the breast with an associated Cytokeratin 7- negative Paget's disease of the nipple. Report of a first case.

Solid papillary carcinoma (SPC) is a rare neoplasm of the breast showing a distinct morphology, neuroendocrine differentiation and should be divided into invasive and in situ subtype according to the current 2012 WHO classification of breast tumors. Here, we describe a case of a pure SPC, invasive-type, in a 31-years old female with an associated mammary Paget's disease (MPD) of the nipple showing a rare, CK7-negative immune phenotype, which has not been reported so far. This unusual differential diagnosis should be added to the rare condition of CK7-negative Paget's disease of the breast and complement a new feature to the characterization of SPC.

The 21-gene recurrence score in special histologic subtypes of breast cancer with favorable prognosis.

BACKGROUND/PURPOSE: The 21-gene recurrence score (RS) assay predicts the likelihood of distant recurrence and chemotherapy benefit in early-stage, estrogen receptor (ER)-positive, HER2-negative breast cancer. Data on the RS of special histologic subtypes of invasive breast carcinoma with favorable prognosis are limited. METHODS: We reviewed our institutional database to identify patients with special histologic subtypes of breast cancer associated with favorable prognosis and available RS results. Our cohort consists of fifty-seven women: thirty-three patients with pure mucinous carcinoma (MC), ten with tubular carcinoma (TC), nine with encapsulated papillary carcinoma (EPC), and five with solid papillary carcinoma (SPC). RESULTS: Most (44/57, 77.2%) carcinomas had low RS (≤17), and none had high RS (≥31). All EPCs had low RS, but other subtypes had RS 18-30. Higher RS was associated with lower progesterone receptor (PR) expression by immunohistochemistry and lower PR mRNA scores (P ≤ 0.007). No morphologic feature (tumor grade, biopsy site changes, cellular stroma, inflammatory cells) was associated with RS ≥ 18. At a median follow-up of 40 months, the distant recurrence-free survival was 100%. One patient with SPC developed locoregional recurrence at 22 months. CONCLUSIONS: As the largest series to date, our study raises the question of whether the RS assay is necessary for breast cancers with favorable histology. Reflex testing of node-negative, ER+/HER2- breast cancers may be deferred for these special histologic subtypes, emphasizing the need for multidisciplinary discussions between breast pathologists and other members of the breast cancer team.

A pilot evaluation of magnetic resonance imaging characteristics seen with solid papillary carcinomas of the breast in 4 patients.

BACKGROUND: Solid papillary carcinoma (SPC) is a rare variant of breast papillary carcinoma with unique pathological morphology and biological behavior. There is only one case report on T1-MRI of SPC. In this study, we report our findings on this new category of papillary carcinoma to fill the gap in MRI characterization of SPC. METHODS: This retrospective study included four pathology-confirmed in situ SPC patients. Conventional MRI, diffusion weighted imaging (DWI), and magnetic resonance spectroscopy (MRS) were performed with a 1.5 T whole-body MR scanner before surgical operation. The following characteristics of each lesion were recorded: signal intensity on T2WI/STIR and T1FSPGR, morphology, maximum lesion size, and time intensity curve (TIC) on dynamic contrast enhancement MRI (DCE-MRI), apparent diffusion coefficient (ADC) value from DWI, and Cho peak from MRS. RESULTS: Signal intensities of all lesions were heterogenous on T2WI/STIR and T1FSPGR. Mass enhancements were observed for all lesions with either oval or irregular shapes on DCE-MRI. The maximum lesion size ranged from 0.8 cm to 3.2 cm. All lesion margins were circumscribed, and internal enhancements were homogeneous or heterogeneous from DCE-MRI. TIC appeared with a rapid increase in initial contrast phases of all lesions. All lesions on DWI (b = 1000s/mm2) were slightly hyperintense with an ADC value range of 1.3 × 10-3 mm2/s to 1.9 × 10-3 mm2/s. Cho peak was absent at 3.2 ppm for all lesions. CONCLUSIONS: MRI characteristics of SPC include heterogeneous signal intensity within the lesion on T2WI/STIR and T1FSPGR, mass enhancement with circumscribed margins, either oval or irregular shapes, and a rapid initial enhancement of TIC on DCE-MRI. ADC values and the absence of Cho peak may provide valuable information to distinguish SPC from other invasive breast carcinomas.

Composite encapsulated papillary carcinoma and solid papillary carcinoma.

Encapsulated papillary carcinoma (EPC) and solid papillary carcinoma (SPC) are distinctive variants of intraductal papillary carcinomas, each accounting for <1% of breast carcinomas. Here we report a composite carcinoma consisting of EPC and SPC. A 73-year-old woman was found to have a high density mass in the left breast on mammogram. A biopsy showed intermediate to high grade ductal carcinoma in situ (DCIS). Gross examination of the lumpectomy specimen revealed a solid, multinodular mass. Microscopic examination demonstrated two morphologically distinct intraductal carcinomas intermingled with each other. One had delicate papillae in multi-cystic spaces surrounded by thick fibrous capsule, consistent with EPC. The other had solid tumor nests with delicate fibrovascular cores. The cells were monotonous with round nuclei and salt and pepper-like chromatin, characteristic of SPC. The lack of myoepithelial cells within the papillae and at the periphery of the lesion was confirmed by immunostaining for p63 and CK5/6. Neuroendocrine differentiation of SPC was demonstrated by neuron specific enolase staining. To our knowledge, this is the first reported case of composite EPC and SPC. It raises an interesting question as to a possible common pathway of carcinogenesis of these two rare variants.

Endocrine mucin-producing sweat gland carcinoma occurring on extra-facial site: a case report.

Cutaneous endocrine mucin-producing sweat gland carcinoma (EMPSGC) is a very rare low-grade malignant neoplasm analogous to the mammary solid-papillary carcinoma. It frequently expresses neuroendocrine markers and may show mucinous differentiation. Although the nodules are circumscribed, myoepithelial cells cannot be showed in most cases and about half of the cases are associated with invasive mucinous carcinoma. Hence, it has been suggested to be invasive and the precursor lesion of some primary cutaneous mucinous carcinomas. After being recognized as a distinct entity, all cases reported to date occurred either in the periocular region or on the cheek. Two thirds of the patients were female. Herein we present an unusual case of in situ EMPSGC on the chest wall skin of a middle-aged man.

Solid Papillary Carcinoma with Invasion in the Male Breast: A Case Report and Literature Review.

Introduction: Solid papillary carcinoma (SPC) accounts for approximately 1% of all breast cancer cases and occurs primarily in postmenopausal women. We report a rare SPC with invasion in the male breast. Case Presentation: A 73-year-old Japanese man presented with bloody nipple discharge and a palpable left breast mass. Mammography revealed a well-defined high-concentration mass. Ultrasonography scans demonstrated an intracystic 10 mm mass under the left nipple without enlarged axillary lymph nodes. A core needle biopsy revealed a ductal carcinoma with nuclear grade 1, which excluded an invasive carcinoma. Magnetic resonance imaging exhibited a 7 mm intense early enhancement in the left breast. A left mastectomy and sentinel lymph node biopsy were performed. The patient was diagnosed with pathological stage IA (T1b N0 M0) breast carcinoma, an invasive pure SPC type without neuroendocrine markers. The patient was treated with oral tamoxifen and survived without any recurrence for 12 months. Conclusion: Invasive SPC of the male breast may occur as a palpable mass or nipple discharge in older men and has a good prognosis.

A morphological and immunohistochemical study of ductal carcinoma in situ, invasive breast carcinoma of no special type, and mucinous carcinoma of the breast in comparison with solid papillary carcinoma regarding neuroendocrine marker expression.

The exact relationship between solid papillary carcinoma (SPC) and invasive breast carcinoma of no special type (IBC-NST) with neuroendocrine differentiation and SPC and mucinous carcinoma (MC) of the breast remains unclear. To clarify the relationship, we conducted a comparative study of morphological and neuroendocrine features between ductal carcinoma in situ (DCIS, 72 cases) and SPC in situ (35 cases), and IBC-NST (103 cases) and invasive SPC (92 cases). We also conducted the study between MC associated with and without SPC. Synaptophysin, chromogranin A, and INSM1 were employed for the immunohistochemical study. IBC-NST had occasionally a morphological similarity with invasive SPC. While 123 of 127 cases with SPC demonstrated diffuse staining with one or more of the neuroendocrine markers, the only one case of DCIS and none of IBC-NST showed it. Type B was observed in 16 of 18 cases of MC associated with SPC and in 13 of 33 cases of MC without it. All the cases of MC with SPC and 6 of 33 cases without it showed diffuse staining for at least one of the neuroendocrine markers. In conclusion, a careful distinction between invasive SPC and IBC-NST with neuroendocrine differentiation is required. We assume that SPC in situ is a potential candidate for precursor of IBC-NST with neuroendocrine differentiation. MC of the breast is suggested to have two pathogenetic pathways through SPC in situ or non-SPC in situ. SPC in situ is thought to be less common as a precursor of MC than non-SPC in situ.

Interesting Breast Tumours: A Tripod of Cases.

Knowledge regarding the lesser common breast tumours, including malignant papillary neoplasms and glycogen-rich clear cell carcinoma, is limited. Overall, cases of papillary carcinoma of the breast fare better than invasive breast carcinoma, from the data available in literature. Glycogen-rich clear cell carcinoma is characterized by the presence of clear cells, having mostly a poorer prognosis. We hereby present three such cases which would add to the existing available information. Case 1 is a 79-year-old female who presented with a left breast lump and bloody nipple discharge. Mammography suggested malignant lesion, with FNAC suspicious of malignancy. Surgery was done and histopathological examination showed irregular islands of tumour cells having papillary fronds with absence of myoepithelial layer. Immunohistochemically, the tumour was GATA3, CK7, ER, PR positive, HER2 negative, with Ki67 index 10%. The case was diagnosed as Solid papillary carcinoma. Case 2 is a 57-year-old female presenting with a left breast lump along with bloody nipple discharge. Mammography and FNAC were in favour of malignancy. Trucut biopsy was done, microscopy revealing a tumour having >90% papillary architecture with infiltrative pattern. Features were suggestive of Invasive breast carcinoma with papillaroid features. The tumour was GATA3, CK7, ER, PR positive, HER2 negative, with Ki67 index 15%. Case 3 is a 70-year-old female presenting with a right breast lump with nipple retraction. Mammography and FNAC were suggestive of malignancy. Trucut biopsy followed by microscopy revealed polygonal tumour cells with clear cytoplasm in nested pattern, showing positive staining for Periodic Acid Schiff. Immunostaining showed GATA3 positive, PAX8 negative, ER and PR positive, HER2 negative, and Ki67 index 20%. A diagnosis of Invasive breast carcinoma with Glycogen-rich clear cell pattern was made. Identifying these rare entities is important along with assessing hormone status for avoiding overtreatment and undertreatment and applying appropriate targeted therapies.

Cytological study of 44 cases with solid papillary carcinoma and a systemic review of solid papillary carcinoma and neuroendocrine tumor of the breast.

BACKGROUND: Solid-papillary carcinoma (SPC) of the breast is a rare variant of low-grade in situ and invasive carcinoma but there are only a few of the cytologic studies. METHODS: We examined 44 cases of SPC of the breast to define the cytologic features. We also made a systemic review of reported cases of SPC and neuroendocrine tumor (NET) of the breast. RESULTS: Both of our and the reviewed cases with SPC were very similar in the cytologic finding. It included hypercellularity, highly discohesive clusters, numerous isolated cells, small nuclei, finely granular chromatin of salt-and-pepper appearance, inconspicuous nucleoli, low nuclear-cytoplasmic ratio, and a plasmacytoid appearance. Moreover, SPC and NET had frequently all of these features in common. Capillary vessels structures and mucinous substance were not frequently seen in our and the reviewed cases with SPC. Rosette and pseudorosette were very rare in the cytologic specimen. The immunocytochemistry with our 9 cases with SPC indicated diffuse positivity for chromogranin A and/or synaptophysin. CONCLUSION: Many cytologic features are frequently shared by SPC and NET of the breast. However, the vascular structure may not be a precise criterion for SPC. Rosette and pseudorosette are rarely helpful for the cytologic diagnosis.

A large-scale clinicopathological and long-term follow-up study of solid papillary carcinoma of the breast.

Solid papillary carcinoma of the breast (SPC) is a rare tumor of the breast with the unique histology and frequent neuroendocrine differentiation. However, a real nature and diagnostic importance of the neuroendocrine differentiation have not been properly handled. And relationship between SPC and the other types of invasive breast carcinoma, especially neuroendocrine tumor of the breast (NETb), has not been fully explained. We conducted a clinicopathological study of SPC to tackle these problems.In the study, we included 127 cases of SPC with long-term follow-ups of up to 30 years. The incidence in the breast carcinoma was 2.0%. The patients with SPC had a significantly better prognosis and no patients died of the tumor. The 35 cases had only SPC in situ (SPC-IS), while the 92 cases had both SPC-IS and SPC with invasion (SPC-INV). Immunohistochemically, 123 of the 127 cases exhibited diffuse expression of one or more neuroendocrine markers. Fifty of the 92 cases had exclusively invasive SPC (iSPC) as the invasive component. Twenty-two cases of iSPC were combined with NETb and the 18 cases with MUC. Six of 8 cases with metastatic SPC-INV disclosed iSPC in the axillary lymph node.This study suggests that SPC is immunohistochemically compatible with NET of the systemic organs (NETs). And the unique morphology of SPC may represent a traditional histology of NETs. The study also indicates that SPC has close relationship between NETb and type B MUC. And SPC and NETb may represent a spectrum of the same disease.

Invasive Micropapillary Carcinoma of the Breast With Solid Papillary Carcinoma: A Case Report.

Invasive micropapillary carcinoma and Solid papillary carcinomas are rare histologic subtypes of breast cancer. Co-existence of tumors of the breast like invasive ductal and lobular carcinomas, or invasive ductal carcinoma and mucinous carcinomas have been reported before. But the existence of invasive micropapillary carcinoma with solid papillary carcinoma is a rare occurrence. Here, we are reporting a rare case of a 60-year-old female with a mass in her left breast. The histopathology report showed a tumor containing these two histologic subtypes. Recognition of all tumor subtypes is necessary, as this can impact the treatment strategy.