Optimal management of a lesion yielding radial scar (RS) without epithelial atypia on breast biopsy is controversial. In this single-institution study spanning 17 years, 53 patients with this biopsy diagnosis were evaluated in terms of clinical, radiologic, and pathologic features and outcomes. RSs were categorized as either “incidental” or as the “targeted” lesion according to defined criteria. Of 48 patients who underwent surgical excision after a diagnosis of RS on biopsy, only 1 had an “upgrade” diagnosis of malignancy (2%). No “incidental” RS was associated with the presence of malignancy on surgical excision. Meta-analysis of 20 RS excision studies demonstrated an overall upgrade rate of 10.4%, with a higher rate in patients with a diagnosis of RS with atypia (26%). The upgrade rate for RS without atypia was 7.5% overall. The lower rate of upgrade to malignancy in this study (2%) is likely related to the thorough radiologic-pathologic review undertaken. In the setting of multidisciplinary agreement and careful radiologic-pathologic correlation, it may be appropriate for patients with a biopsy diagnosis of RS without atypia to forego surgical excision in favor of imaging follow-up.

Results: 53 patients with 54 lesions were diagnosed as having a PT. The median age was 27.5, 35.0 and 38.5 years for benign, borderline and malignant PT, respectively. Borderline and malignant PTs were larger than benign PTs, with mean sizes of 33 and 42 mm compared with 29 mm. 38% of PTs were labelled by the reporting radiologist as fibroadenomas, including two borderline PTs and one malignant PT. In 24% of cases, the radiologist raised the possibility of PT in the report. 17 patients (40%) developed a new fibroepithelial breast lesion during follow-up of which 4 were recurrent PTs. Conclusion: Despite adequate surgical management, the development of further fibroepithelial lesions in the ipsilateral breast is common. 3-year clinical surveillance, with the addition of 6-monthly ultrasound is advised for females with initial borderline or malignant PT histology. Advances in knowledge:We propose a follow-up protocol with ultrasound based on the grade of the PT diagnosed for 3 years to detect recurrence.Phyllodes tumours (PTs) are rare biphasic fibroepithelial neoplasms accounting for ,1% of all breast lesions. 1 In the literature, they have been described as occurring in females aged 35-55 years, typically 15-20 years older than females with fibroadenomas (FAs) and with a higher incidence in Asian females.2,3 Imaging findings of PT and FA overlap and as such lesions may be misdiagnosed. 4 Histologically, PTs can be identified by their distinctive leaf-like architecture and increased stromal cellularity. 5 Typically, PTs present as a palpable breast lump and were traditionally differentiated from FAs based on their larger size at presentation.6 However, with increased breast awareness and screening programmes, smaller and incidental lesions are being found on imaging. 6 In symptomatic breast clinics, including this institution, "triple assessment" consisting an initial physical examination, followed by radiological imaging (ultrasound and/or mammography) and histological sampling either by fine-needle aspiration cytology (FNAC) or core biopsy is the standard diagnostic pathway for palpable breast lesions. The purpose of triple assessment is to provide a more accurate pre-operative diagnosis to ensure proper surgical planning and avoiding re-excision or tumour recurrence. 7According to the World Health Organization criteria, there are two grading systems for PTs; a two-tiered system or a three-tiered system. 8 Our institution employs the threetiered system, the subgroups being benign, borderline and malignant. Grading is based on semi-quantitative assessment of stromal cellularity, cellular pleomorphism, mitotic activity, margin appearance and stromal distribution. The standard procedure for treatment, no matter what the grade of the PT, is surgical wide local excision, preferably with clear margins of at least 1 cm. However, owing to the fact that most PTs are not fully diagnosed pre-operatively, initial surgery does not always provide adequate margins necessitating frequent post-operative re-excision of the margi...

Pure apocrine carcinoma of the breast is rare and has been defined by using a combination of morphologic (apocrine morphology in >90% of tumour cells) and immunohistochemical criteria (oestrogen receptor (ER) and progesterone receptor (PR) negative and androgen receptor (AR) positive). Recent advances in the molecular classification of breast tumours have uncovered a subset of breast tumours associated with high expression of androgen receptor mRNA including the so-called ‘luminal androgen receptor (LAR) tumours’ and ‘molecular apocrine tumours’ (MATs). Recognition of these tumour subsets has opened potential avenues for therapies exploiting the AR pathway in triple negative breast carcinoma (TNBC). In this second part of our two-part review, we focus on the definition of pure apocrine carcinoma, recent advances in understanding the molecular apocrine signature in breast carcinoma, its relationship to pure apocrine carcinoma defined at the level of light microscopy and immunohistochemistry (IHC) and the therapeutic implications of androgen expression in TNBC. We complete the article with a summary of the utility of IHC in stratifying apocrine lesions of the breast.

Angiosarcomas are malignant tumours of endovascular origin. They are rare tumours accounting for 0.04-1% of all breast malignancies. Two different forms are described: primary, occurring in young women, and secondary angiosarcoma, which occurs in older women with a history of breast-conserving surgery and radiation therapy. Imaging findings on mammography and ultrasound are non-specific, but magnetic resonance imaging with dynamic contrast enhancement is more informative. We present two cases - one of primary and one of secondary angiosarcoma - and review the imaging findings.

Apocrine change is recognised in benign, atypical and malignant lesions of the breast. Apocrine metaplasia, a frequent finding in the breast of women over the age of 25 years, is most commonly seen in benign cysts with a simple or papillary configuration. Apocrine change is also recognised in other benign lesions including sclerosing adenosis, now known as apocrine adenosis. Apocrine atypia usually refers to cytological atypia in which there is at least threefold variation in nuclear size but architectural atypia may also occur. The distinction between atypical apocrine hyperplasia and non-high-grade apocrine ductal carcinoma in situ may be difficult due to the relative rarity of these entities and the lack of validated diagnostic criteria. Lobular carcinoma in situ (LCIS) with apocrine change is considered to be a variant of pleomorphic LCIS. An apocrine variant of encapsulated papillary carcinoma is also recognised. Apocrine change is described in invasive carcinoma, including no special type, lobular, micropapillary and mucinous variants. The recent WHO 2019 update recognises ‘carcinoma with apocrine differentiation’ as a special type breast carcinoma based on the presence of apocrine morphology in at least 90% of the tumour. Tumours with apocrine morphology are usually but not always hormone receptor negative. Human epidermal growth factor receptor 2 (HER-2) status is variable. Molecular studies have identified breast tumours with apocrine features and high expression of androgen receptor mRNA including ‘luminal androgen receptor tumours’ and ‘molecular apocrine tumours’. The term ‘pure apocrine carcinoma’ has been proposed to describe an invasive carcinoma with apocrine morphology that is oestrogen and progesterone receptor negative and androgen receptor positive. HER-2 status may be positive or negative. This article reviews the pathology of benign, atypical and malignant apocrine lesions of the breast, with emphasis on diagnostic criteria including an approach to evaluation of apocrine lesions on needle core biopsy, and recent advances in our understanding of invasive apocrine carcinoma.

Apocrine morphology is a common phenomenon encountered in everyday breast pathology practice, and is defined as cuboidal or columnar cells exhibiting abundant eosinophilic granular cytoplasm, prominent apical granules, a low nuclear-cytoplasmic ratio, and round nuclei with pale chromatin and prominent nucleoli. Apocrine morphology is recognised in benign, atypical and malignant lesions of the breast. The morphology of apocrine atypia and non-high-grade apocrine ductal carcinoma in situ (DCIS) is less well defined due to the relative rarity of these lesions. In part 1 of this two-part review, we focus on the morphological characteristics of benign, atypical and in situ apocrine lesions of the breast, summarise the available data to date regarding distinction of atypical apocrine proliferations from non-high-grade apocrine DCIS and the biological significance of apocrine atypia, and provide practical guidance on handling these difficult lesions. Part 2 of this review will focus on the concept of pure apocrine carcinoma with emphasis on its definition and molecular data, including the current understanding of the molecular apocrine signature in breast carcinoma. We complete the review with a synopsis on the utility of immunohistochemistry in the diagnosis of apocrine lesions of the breast.

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Tumor-induced osteomalacia (TIO) is an ultrarare disorder that is caused by renal phosphate wasting due to uncontrolled tumoral production of fibroblast growth factor 23 (FGF23) from phosphaturic mesenchymal tumors. Surgical removal of the tumor is curative. There is limited information on the biochemical changes in mineral metabolism and bone remodeling activity after surgery, but it is reported that surgery is followed by a hungry bone syndrome (HBS) with hypocalcemia and secondary hyperparathyroidism. We report the biochemical response to surgery in two patients, who presented with severe TIO, as manifested by proximal myopathy, multiple stress fractures, high FGF23, low serum phosphate, low maximum renal phosphate reabsorption threshold (TmP/GFR), and low 1,25-dihydroxy-vitamin D (1,25(OH) 2 D). Prior to surgery, both patients developed secondary hyperparathyroidism and one case had progressed to tertiary hyperparathyroidism. After surgery there was normalization of FGF23, TmP/GFR, and phosphate. High 1,25(OH) 2 D was recorded. One patient had hypocalcaemia and worsening secondary hyperparathyroidism consistent with HBS; the other patient did not have hypocalcemia but had worsening tertiary hyperparathyroidism that only resolved with cinacalcet. There was a marked increase in bone remodeling markers, both resorption and formation, consistent with a high bone turnover state. There was a different pattern of change in bone specific alkaline phosphatase, reflecting healing of osteomalacia. Biochemical monitoring in the post-surgical management of TIO is warranted for guiding adjustments in medical intervention, both short-term and long-term. Future use of burosumab prior to surgery for TIO may ameliorate the immediate post-surgery effects.