Distinct Uroplakin II Staining Pattern in Apocrine Breast Carcinoma.

Uroplakin II (UPII) has been shown as a highly specific marker of urothelial carcinoma; however, it can also stain subtypes of apocrine-differentiated breast carcinoma. Given that urothelium and breast epithelium share other common immunohistochemical markers, such as CK7 and GATA3, this can lead to a potential diagnostic pitfall. We stained a cohort of triple-negative breast cancer with UPII. Compared with the diffuse, cytoplasmic staining in urothelial carcinoma, UPII was positive in 38.9% of apocrine carcinoma (7/18) with a course, granular cytoplasmic staining pattern and negative in all nonapocrine triple-negative breast cancer cases. Furthermore, the same staining pattern was present in all apocrine metaplasia of the breast (4/4) and apocrine sweat glands in normal skin (6/6). This distinct subcellular localization of UPII staining in breast carcinoma can offer a potential solution to the above diagnostic pitfall.

Immunohistochemical analysis of IDH2 R172 hotspot mutations in breast papillary neoplasms: applications in the diagnosis of tall cell carcinoma with reverse polarity.

Tall cell carcinoma with reverse polarity is a rare subtype of breast carcinoma with solid and papillary growth and nuclear features reminiscent of those of the tall cell variant of papillary thyroid carcinoma. These tumors harbor recurrent IDH2 R172 hotspot mutations or TET2 mutations, co-occurring with mutations in PI3K pathway genes. Diagnosis of tall cell carcinomas with reverse polarity is challenging in view of their rarity and the range of differential diagnosis. We sought to determine the sensitivity and specificity of IDH2 R172 immunohistochemistry for the detection of IDH2 R172 hotspot mutations in this entity. We evaluated 14 tall cell carcinomas with reverse polarity (ten excision and five core needle biopsy specimens), 13 intraductal papillomas, 16 solid papillary carcinomas, and 5 encapsulated papillary carcinomas by Sanger sequencing of the IDH2 R172 hotspot locus and of exons 9 and 20 of PIK3CA, and by immunohistochemistry using monoclonal antibodies (11C8B1) to the IDH2 R172S mutation. The 14 tall cell carcinomas with reverse polarity studied harbored IDH2 R172 hotspot mutations, which co-occurred with PIK3CA hotspot mutations in 50% of cases. None of the other papillary neoplasms analyzed displayed IDH2 R172 mutations, however PIK3CA hotspot mutations were detected in 54% of intraductal papillomas, 6% of solid papillary carcinomas, and 20% of encapsulated papillary carcinomas tested. Immunohistochemical analysis with anti-IDH2 R172S antibodies (11C8B1) detected IDH2 R172 mutated protein in 93% (14/15) of tall cell carcinomas with reverse polarity samples including excision (n = 9/10) and core needle biopsy specimens (n = 5), whereas the remaining papillary neoplasms (n = 34) were negative. Our findings demonstrate that immunohistochemical analysis of IDH2 R172 is highly sensitive and specific for the detection of IDH2 R172 hotspot mutations, and likely suitable as a diagnostic tool in the evaluation of excision and core needle biopsy material of tall cell carcinomas with reverse polarity.

Metastatic breast carcinoma to the urinary bladder-a report of 11 cases including a tumor to tumor metastasis.

Metastatic breast carcinoma to the urinary bladder is rare. Eleven cases of metastatic breast carcinoma to the bladder are described in this report, including one case with a tumor to tumor metastasis. The patients ranged from 51 to 83 years of age. The time intervals between the diagnosis of primary breast cancer and the occurrence of bladder metastases ranged from 41 to 336 months. There were seven cases of invasive ductal carcinoma and four cases of invasive lobular carcinoma. In one case, a lobular carcinoma of the breast metastasized to a concurrent squamous cell carcinoma of the bladder. The immunophenotypic status of estrogen receptor and Her2 expression of the metastatic carcinomas were all concordant with the primary tumors. In nine patients with follow-up available, seven patients died of the disease ranging from 1 to 23 months after the diagnosis of the bladder metastasis and two patients were alive at 5 months of follow-up. To date, this report is the largest single series of patients with breast carcinoma metastatic to the bladder. It is the first reported instance of lobular carcinoma of the breast metastasizing to a squamous cell carcinoma of the bladder.

Sclerosing Odontogenic Carcinoma with Local Recurrence: Case Report and Review of Literature.

Sclerosing odontogenic carcinoma is a rare locally destructive neoplasm with many histologic mimics. Here the diagnostic challenges are presented of a case of sclerosing odontogenic carcinoma with variable histologic features, including unusual and unexpected negative immunostaining for CK19.

Molecular Profiling of Hyalinizing Clear Cell Carcinomas Revealed a Subset of Tumors Harboring a Novel EWSR1-CREM Fusion: Report of 3 Cases.

We describe a novel gene fusion, EWSR1-CREM, identified in 3 cases of clear cell carcinoma (CCC) using anchored multiplex polymerase chain reaction, a next-generation sequencing-based technique. CCC is a low-grade salivary tumor recently characterized to have EWSR1-ATF1 fusions in the majority of cases. Three cases of malignant tumor presenting in the base of tongue, lung, and nasopharynx were studied. All cases shared a clear cell morphology with hyalinized stroma, presence of mucin and p63 positivity and were initially diagnosed as mucoepidermoid carcinoma but were negative for evidence of any of the expected gene fusions. Anchored multiplex polymerase chain reaction demonstrated a EWSR1-CREM fusion in all 3 cases to confirm a diagnosis of CCC. This finding is biologically justified as CREM and ATF1 both belong to the CREB family of transcription factors. EWSR1-CREM fusions have not been previously reported in CCC and have only rarely been reported in other tumors. We show that the ability to discover novel gene variants with next-generation sequencing-based assays has clinical utility in the pathologic classification of fusion gene-associated tumors.

The Significance of the Stromal Response in Breast Cancer: An Immunohistochemical Study of Myofibroblasts in Primary and Metastatic Breast Cancer.

BACKGROUND: Gene expression profiling of breast cancer has demonstrated the importance of stromal response in determining the prognosis of invasive breast cancer. The host response to breast cancer is of increasing interest to pathologists and may be a future focus for novel pharmacological treatments. METHODS: This study describes the pattern of distribution of stromal myofibroblasts using immunostains for CD10 and smooth muscle actin (SMA) in 50 primary breast cancers and their matched nodal metastases (68.6% nodes positive and 31.4% nodes negative). The stroma within the tumor (intratumoral) and at the advancing tumor edge (peri-tumoral) was studied in both primary and nodal sites. A simple quantitative scoring system was employed for both immunostains. The correlation between expression of these markers by stromal cells and standard pathological prognostic factors of stage, grade, hormone receptor and Her-2 status was analysed. RESULTS: SMA-positive stromal cells were more abundant in peri-tumoral stroma compared with intratumoral stroma in both primary and metastatic lesions. SMA expression in the lymph node metastases showed a significant correlation with tumor stage. SMA expression in peri-tumoral stroma correlated with Her-2 status. CONCLUSION: The results of this study suggest that myofibroblasts, particularly those expressing SMA, might potentiate the progression of the carcinomatous process especially in nodal metastases. Thus these cells may be a potential therapeutic target.

Metastatic non-small cell lung carcinoma a mimic of primary breast carcinoma-case series and literature review.

Metastatic tumors to the breast are rare but constitute a major diagnostic dilemma. Of these, non-mammary carcinomatous metastases to the breast are particularly challenging and, without a clinical history, may be extremely difficult to distinguish from primary breast carcinoma (PBC). We specifically studied metastatic tumors of pulmonary origin, as the lung is one of the major primary sites for carcinomatous metastasis to breast. Sixteen metastatic lung tumors to the breast were identified in our archives between 1996 and 2017 including 12 non-small cell lung carcinomas (NSCLC), one large-cell neuroendocrine, one atypical carcinoid, and two small-cell carcinomas. Adenocarcinoma was the most frequent amongst the NSCLCs (11/14). We retrieved the clinical information of these cases and reviewed the pathological characteristics to provide practical tools for pathologists to aid in their identification. Even in the absence of a clinical history of lung cancer, metastatic pulmonary adenocarcinoma to the breast should be considered in at least one of the following scenarios: (1) single or multiple well-circumscribed lesions of the breast that lack an in situ component and that are accompanied by distant metastases but negative axillary lymph nodes, (2) breast tumors that are triple negative yet not high-grade, or (3) breast tumors presenting as stage 4 disease and/or having an unusually aggressive clinical course on standard breast therapy. Accurate and timely diagnosis of these tumors is mandatory because of treatment and prognostic implications.

Combined Papillary Renal Cell Carcinoma with Neuroendocrine Differentiation and Mucinous Tubular and Spindle Cell Carcinoma.

A unique case of combined papillary renal cell carcinoma (PRCC) and mucinous tubular and spindle cell carcinoma (MTSCC) presenting in a man aged 67 years is reported. The two separate components were distinct on morphological, immunohistochemical (IHC), and genetic grounds, while type 2 PRCC predominated. Three years after the initial diagnosis, the PRCC component metastasized to the lungs where it morphologically mimicked a pulmonary neuroendocrine tumor. Retrospectively focal neuroendocrine differentiation was demonstrated by IHC in the PRCC component of the primary neoplasm.

Post-radiation epithelioid angiosarcoma of the urinary bladder and prostate.

Angiosarcoma of the lower urinary tract is exceedingly rare. A minority of cases are associated with local radiotherapy. Epithelioid angiosarcoma is a variant of angiosarcoma composed of large rounded epithelioid endothelial cells that are positive for cytokeratin on immunostaining. There are only two cases of post-radiation epithelioid angiosarcoma reported in the urinary bladder, and none in the prostate gland. We report a case of epithelioid angiosarcoma involving the urinary bladder and prostate in a patient with a history of radiotherapy for prostatic adenocarcinoma. A brief review of literature regarding post-radiation epithelioid angiosarcomas in the lower urinary tract is discussed.

Practical Considerations in Breast Papillary Lesions: A Review of the Literature.

CONTEXT: -Diagnosis of papillary breast lesions, especially in core biopsies, is challenging for most pathologists, and these lesions pose problems for patient management. Distinction between benign, premalignant, and malignant components of papillary lesions is challenging, and the diagnosis of invasion is problematic in lesions that have circumscribed margins. Obtaining a balance between overtreatment and undertreatment of these lesions is also challenging. OBJECTIVES: -To provide a classification and a description of the histologic and immunohistochemical features and the differential diagnosis of papillary breast lesions, to provide an update on the molecular pathology of papillary breast lesions, and to discuss the recommendations for further investigation and management of papillary breast lesions. This review provides a concise description of the histologic and immunohistochemical features of the different papillary lesions of the breast. DATA SOURCES: -The standard pathology text books on breast pathology and literature on papillary breast lesions were reviewed with the assistance of the PubMed database ( http://www.ncbi.nlm.nih.gov/pubmed ). CONCLUSIONS: -Knowledge of the clinical presentation, histology, immunoprofile, and behavior of papillary breast lesions will assist pathologists with the diagnosis and optimal management of patients with papillary breast lesions.

Molecular subtype profiling of invasive breast cancers weakly positive for estrogen receptor.

The estrogen receptor (ER) is a key predictive biomarker in the treatment of breast cancer. There is uncertainty regarding the use of hormonal therapy in the setting of weakly positive ER by immunohistochemistry (IHC). We report intrinsic subtype classification on a cohort of ER weakly positive early-stage breast cancers. Consecutive cases of breast cancer treated by primary surgical resection were retrospectively identified from 4 centers that engage in routine external proficiency testing for breast biomarkers. ER-negative (Allred 0 and 2) and ER weakly positive (Allred 3-5) cases were included. Gene expression profiling was performed using qRT-PCR. Intrinsic subtype prediction was made based upon the PAM50 gene expression signature. 148 cases were included in the series: 60 cases originally diagnosed as ER weakly positive and 88 ER negative. Of the cases originally assessed as ER weakly positive, only 6 (10 %) were confirmed to be of luminal subtype by gene expression profiling; the remaining 90 % of cases were classified as basal-like or HER2-enriched subtypes. This was not significantly different than the fraction of luminal cases identified in the IHC ER-negative cohort (5 (5 %) luminal, 83(95 %) non-luminal). Recurrence-free, and overall, survival rates were similar in both groups (p = 0.4 and 0.5, respectively) despite adjuvant hormonal therapy prescribed in the majority (59 %) of weakly positive ER cases. Weak ER expression by IHC is a poor correlate of luminal subtype in invasive breast cancer. In the setting of highly sensitive and robust IHC methodology, cutoffs for ER status determination and subsequent systemic therapy should be revisited.

Bilateral Gigantomastia, Multiple Synchronous Nodular Pseudoangiomatous Stromal Hyperplasia Involving Breast and Bilateral Axillary Accessory Breast Tissue, and Perianal Mammary-Type Hamartoma of Anogenital Mammary-Like Glands: A Case Report.

Mammary-type fibroepithelial lesions involving ectopic breast and anogenital region are rare and usually coexist with normal orthotopic breast. We present what we believe to be a unique case of synchronous bilateral gestational gigantomastia resembling fibrous mastopathy, synchronous rapidly growing pregnancy-associated nodular pseudoangiomatous stromal hyperplasia involving right breast and bilateral axillary ectopic breast tissue, and metachronous perianal mammary-type hamartoma involving anogenital mammary-like glands occurring in a 34-year-old patient with facioscapulohumeral muscular dystrophy. Also, we review the literature concerning these lesions.

Syringomatous Structures in Extramammary Paget Disease: A Potential Diagnostic Pitfall.

Primary extramammary Paget disease (EMPD) is a form of intraepithelial adenocarcinoma. Different morphological changes may accompany EMPD, including the presence of syringoma-like structures. The authors report 10 cases of EMPD, all of which manifested syringoma-like structures within the dermis both in areas involved by the carcinoma and beyond, including at the margins of the excisions. All patients were women, whose ages ranged from 49 to 93 years (median 75 years). The possible pathogenesis of the syringoma-like lesions is discussed. Awareness of these structures in vulvectomy specimens for EMPD is important to prevent misinterpretation of the syringoma-like lesions as an invasive component of the EMPD.

Fine-needle aspiration of soft tissue myoepithelioma.

Soft tissue myoepithelioma is a rare neoplasm composed of myoepithelial cells. We describe the cytologic features of a soft tissue myoepithelioma arising in the right lower chest wall in a 65-year-old woman. The fine-needle aspiration (FNA) smears showed round to oval, spindle, epithelioid, and plasmacytoid cells in the myxoid background. The nuclei were uniform, round to ovoid, with finely distributed chromatin and eosinophilic or pale cytoplasm, and resembled lobular carcinoma of breast. Ultrasound guided core biopsy showed the tumor cells had bland cytologic features, arranged in small cords, nests, and dissociated single cells, with no glandular differentiation or breast tissue seen. The tumor cells demonstrated immunoreactivity for cytokeratin (AE1/AE3) and glial fibrillary acidic protein, but were negative for estrogen receptor. Fluorescence in situ hybridization demonstrated the EWSR1 rearrangement, confirming the diagnosis of myoepithelioma.

Glomus tumour of the colon: dynamic contrast-enhanced CT findings and review of the literature.

We describe the peculiar enhancement pattern of a subepithelial colonic glomus tumour on dynamic contrast-enhanced computed tomography. Discontinuous, peripheral nodular enhancement of the colonic lesion followed by subsequent centripetal filling-in of contrast was reminiscent of a hepatic haemangioma, which has not been described with a glomus or any other subepithelial tumour of the colon. When encountered, this tumour enhancement pattern raises the possibility of a colonic glomus tumour prior to histological confirmation.

Encapsulated papillary carcinoma, apocrine type, of the breast.

The apocrine type of encapsulated papillary carcinoma (ECP-A), of the breast is a rare neoplasm and there are only eight cases reported to date. Herein, we report the ninth case. A 68-year-old Japanese woman presented with a left breast mass. The cytoplasm of the tumour cells showed positive immunostaining for GCDFP-15. Myoepithelial cells were absent within the papillary structures and at the periphery of the lesion. The clinical course of the patient was uneventful 11 months after surgery. We postulate that EPC-A belongs to the molecular apocrine type of breast carcinoma.

Metastatic small cell osteosarcoma to the liver: a diagnostic pitfall for fine-needle aspiration cytology.

We report the fine-needle aspiration cytology of a case of metastatic small cell osteosarcoma to the liver with rosette formation, originating from distal femur, in a 36-year-old female. The aspirate of the liver metastases revealed a relatively monomorphic population of mitotically active small blue round cells arranged in clusters with prominent rosette formation simulating a neuroendocrine carcinoma or other rosette-forming small round cell tumors such as Ewing sarcoma. No extracellular mineralized matrix material was present. Comparison of the liver aspirate with the biopsy from the distal femoral lesion was crucial in reaching the correct diagnosis of metastatic small cell osteosarcoma with rosette formation. This is a potential diagnostic pitfall, particularly if interpreted without the knowledge of a suspected primary bone tumor.

Encapsulated papillary carcinoma, apocrine type, of the breast

The apocrine type of encapsulated papillary carcinoma (ECP-A), of the breast is a rare neoplasm and there are only eight cases reported to date. Herein, we report the ninth case. A 68-year-old Japanese woman presented with a left breast mass. The cytoplasm of the tumour cells showed positive immunostaining for GCDFP-15. Myoepithelial cells were absent within the papillary structures and at the periphery of the lesion. The clinical course of the patient was uneventful 11 months after surgery. We postulate that EPC-A belongs to the molecular apocrine type of breast carcinoma.