Case Report: A challenging diagnosis of an apocrine sweat gland carcinoma.

The differential diagnosis for an axillary mass in a patient with a previously treated malignancy is broad and definitive tissue diagnosis is required to guide treatment and surveillance strategies. We present the case of a 76-year-old African American male with a history of prostate cancer who presented with a left axillary mass two years after achieving remission from his prostate malignancy. Due to the diagnostic challenge, this excisional biopsy was reviewed at four different academic centers. Although no universal consensus among these institutions' pathologists, but in the context of clinical presentation and anatomic location, the overall clinical findings are consistent with apocrine sweat gland carcinoma. The mass was treated with complete local surgical excision, though regional lymph node metastasis occurred 2 years later. Multimodal treatment with surgery and radiation was done with removal of regional metastasis and no distant disease was identified. Primary apocrine carcinoma is a rare cutaneous neoplasm with less than 100 reported cases in the literature. A combination of clinical history and presentation, histomorphology, anatomical location, and immunohistochemistry is used to support the diagnosis and ultimately drive management.

Primary cutaneous apocrine carcinoma with RARA::NPEPPS fusion.

Gene fusions have emerged as crucial molecular drivers of oncogenesis in a subset of cutaneous adnexal neoplasms, including poroid neoplasms and hidradenomas. We present a unique case of primary cutaneous apocrine carcinoma harboring RARA::NPEPPS fusion, broadening the spectrum of fusion-associated cutaneous adnexal neoplasms. A 77-year-old African American male presented with an ulcerated thigh nodule. Histopathologically, the predominantly dermal-based adenocarcinoma exhibited papillary, micropapillary, cribriform, and solid growth patterns with central comedonecrosis, set in a fibrotic/desmoplastic stroma. Immunophenotypically, the neoplastic cells were positive for CK7, CK19, GATA3, TRPS1, HER2, CK5/6, calretinin, p63, and DPC4 (no loss), while lacking immunoreactivity for CK20, CDX2, TTF1, napsin-A, PAX8, arginase-1, adipophilin, NKX3.1, uroplakin II, and D2-40. The immunoprofile and clinical and radiographic absence of any internal malignancy, including breast carcinoma, except for multiple lymphadenopathy, supported the diagnosis of primary cutaneous apocrine carcinoma. Next-generation sequencing unveiled the novel RARA::NPEPPS fusion, concurrent ERBB2 amplification, and multiple somatic mutations involving TP53, CDKN2A, BRCA2, PIK3CA, PIK3R1, and others. The patient developed widespread metastases within a year after the initial diagnosis, indicating the tumor's aggressive behavior. This novel fusion, unprecedented in any human malignancies including primary cutaneous adnexal carcinomas, may suggest a potential new subtype within primary cutaneous adnexal carcinoma.

Apocrine carcinoma with marked sebocyte-like cytological features: A report of two cases.

Apocrine carcinoma cases with sebaceous differentiation have not been reported and can be misdiagnosed as sebaceous carcinoma. We present two cases of apocrine carcinoma with marked sebocyte-like cytological features. Tumors were observed in the left axilla of a 68-year-old man (Case 1) and the right axilla of a 72-year-old man (Case 2). Both patients presented with multiple lymph node metastases. Histopathology revealed densely distributed solid nests of tumor cells containing foamy cytoplasm and enlarged round nuclei with prominent nucleoli. The tumor cells diffusely expressed adipophilin, PRAME (cytoplasmic pattern), androgen receptor, BerEP4, and GCDFP15 but did not express p63 in both cases. PIK3CA E726K and H1047R mutations were detected in Cases 1 and 2, respectively. Tumor location in the axilla, the presence of eosinophilic granular cytoplasm, prominent nucleoli, and PIK3CA mutations, immunoreactivity for BerEP4 and GCDFP15, and lack of p63 immunoexpression findings matched apocrine carcinoma characteristics, but not sebaceous carcinoma. Thus, apocrine carcinoma can demonstrate intracytoplasmic lipid accumulation and rarely exhibit sebocyte-like cytological features. Apocrine carcinoma should be distinguished from sebaceous carcinoma due to the former's higher metastatic potential and lack of association with Muir-Torre syndrome.

Clinicopathological Characteristics and Prognosis of Triple-Negative Apocrine Carcinoma: A Case-Control Study.

Background: With a prevalence of only 1% among all breast cancers in Japan, apocrine carcinoma (AC) is a rare type of breast cancer, and its clinicopathological characteristics remain unclear. The aim of this study was to evaluate the characteristics and prognosis of AC, in relation to the presence or absence of androgen receptor (AR). Methods: We conducted a retrospective multi-center case-control study (Yokohama Clinical Oncology Group (YCOG): YCOG1701 study) in Japan. A total of 53 patients were registered who were diagnosed with AC between 2000 and 2017 in YCOG-affiliated hospitals. Results: The median age of the patients was 67 (43 - 94) years, and the median observation time was 6.1 years. Among the 53 cases, 24 had triple-negative pure AC (TN-PAC; AR-positive), whereas 29 had other types of AC (other-AC; estrogen receptor-positive and/or human epidermal growth factor receptor 2-positive or AR-negative). Tumor size was smaller (1.4 vs. 2.1 cm, P = 0.024) and metastasis occurred in fewer nodes (12.5% vs. 37.9%, P = 0.036) in the TN-PAC group than in the other-AC group. The number of patients who were administered perioperative adjuvant chemotherapy did not significantly differ between the two groups (TN-PAC/other-AC = 50.0%/55.2%, P = 0.525); however, there was no recurrence in the TN-PAC group, compared to five cases with relapse in the other-AC group. Conclusions: AR-positive AC patients showed a favorable prognosis without adjuvant chemotherapy, even with the TN subtype. A clinical trial exploring the possibility of treatment de-escalation is anticipated.

Apocrine carcinoma-and-malignant myoepithelioma in a dog: a case of simultaneous malignant progression of both luminal epithelium and myoepithelium.

A 9-y-old male Boxer dog developed a mandibular skin tumor, which histologically had a locally invasive growth pattern composed of bilayered structures of inner eosinophilic cuboidal tumor cells and outer clear polygonal tumor cells with cytoplasm containing glycogen granules. Both cell populations gradually changed from low-grade morphologic features to highly anaplastic ones. Immunohistochemically, the eosinophilic tumor cells were positive for cytokeratin 8, a useful marker for luminal epithelial cells. In contrast, the clear tumor cells expressed several myoepithelial markers, including α-smooth muscle actin, p63, and cytokeratin 14. Based on these histologic and immunohistochemical characteristics, we diagnosed this apocrine sweat gland tumor as a carcinoma-and-malignant myoepithelioma with high-grade transformation of both luminal and myoepithelial cells. Our case may be a helpful reference for the histogenesis of carcinoma-and-malignant myoepithelioma, in which both the luminal epithelial and myoepithelial components are malignant.

Prognostic factors in cutaneous apocrine carcinoma: a single-institution retrospective study of 32 patients.

BACKGROUND: Cutaneous apocrine carcinoma (CAC) is a rare adnexal carcinoma. Limited data exists on the demographics and overall survival (OS) of patients with CAC; thus, there is no consensus on surgical management. This study aimed to examine demographic and survival data of patients with CAC to determine optimal surgical management. METHODS: A single-center retrospective cohort study was conducted at the National Cancer Center Hospital in Tokyo between 2005 and 2022. Patients with a histologically-confirmed CAC diagnosis were identified and data on patient demographics, OS, and lymph node (LN) status were gathered. RESULTS: Thirty-two patients were included (median age, 65.5 years; male-female ratio, 15:1). The most common involvement site was the axilla (87.5%). Of the nine patients in the clinical local stage, pathological LN metastases were found in five patients. Either pathological LN or distant metastases were present in 75% of the patients at initial diagnosis. The most common initial surgical treatments included wide local excision and complete LN dissection. Across cohorts, the median OS was 39 months. Patients with ≥ 4 LN metastases had reduced recurrence-free survival and OS compared to those with ≤ 3 LN metastases (p = 0.042, p = 0.041, respectively). The OS was not remarkably different between patients who did and did not receive postoperative radiation therapy. CONCLUSIONS: Since CAC has a high rate of LN metastasis-and the number of LN metastases is a significant prognostic factor-LN evaluation should be considered for patients with CAC as initial treatment. Nonetheless, ≥ 4 LN metastases can be a poor prognostic factor for CAC.

Primary cutaneous apocrine carcinoma, arising in tubular apocrine adenoma.

Primary cutaneous apocrine carcinoma is a rare adnexal tumor that arises from apocrine progenitor cells. These tumors may be associated with benign apocrine hyperplasia, and a longstanding history of a lesion should not preclude a malignant diagnosis. We report a case of a 70-year-old female who presented to the clinic with a 3-year history of an asymptomatic vulvar lesion. An excisional biopsy was performed. Histopathologic examination revealed a tumor with two distinct components. The first component was determined to be a benign tubular apocrine adenoma. The second component, arising within the apocrine adenoma, was determined to be an apocrine carcinoma based on histopathologic features and immunohistochemical profile. Twelve months after subsequent wide local excision and sentinel node biopsy, the patient is alive without recurrence.

Multiomic analysis of HER2-enriched and AR-positive breast carcinoma with apocrine differentiation and an oligometastatic course: a case report.

Breast carcinoma is the most prevalent cancer among women globally. It has variable clinical courses depending on the stage and clinical-biological features. This case report describes a 56-year-old female with invasive breast cancer without estrogen or progesterone receptor expression, with apocrine differentiation, and with no germline variants in the BRCA1 and BRCA2 genes. Throughout the clinical course, the patient exhibited discordant results for HER2 in immunohistochemistry and in situ hybridization. During the second relapse, the disease displayed apocrine microscopic features. The tumor underwent analysis for the androgen receptor, GCDFP-15, RNA-seq, and whole-genome sequencing (WGS) to identify the breast cancer subtype and to characterize the cancer genome. Our bioinformatic analysis revealed 20,323 somatic SNV/Indels, including five mutations in cancer-related genes that are believed to be responsible for the tumor's development. Two of these mutations were found in the PIK3CA and TP53 genes. Furthermore, the tumor tissue exhibited large copy number alterations to the chromosomes, which could impact gene expression through complex mechanisms and contribute to the tumor phenotype. Clustering algorithms applied on RNA-sequencing data categorized this cancer as a HER2+ subtype. The second-line capecitabine chemotherapy treatment is ongoing, and the patient is responding well. Bioinformatic results support the current treatment decision and open the way to further treatments.

Pregnancy Associated Invasive Apocrine Carcinoma of the Breast: Case Report from Ethiopia.

We present a case report on a case of invasive apocrine carcinoma of breast during pregnancy at a tertiary referral hospital in Ethiopia. The patient's case in this report signifies the challenging clinical situation that the patient, developing fetus and treating physicians have to go through and the need to improve maternal-fetal medicine and oncologic setup and treatment guidelines in Ethiopia. Our case also illustrates the huge disparity between the management of both breast cancer and its occurrence during pregnancy in low-income countries like Ethiopia and developed nations elsewhere. Our case report shows a rare histological finding. The patient has invasive apocrine carcinoma of the breast. To our knowledge, it is the first case to be reported in the country.

Malignant adnexal tumor of the skin on breast: A case report of apocrine carcinoma.

INTRODUCTION: Malignant adnexal tumors of the skin (MATS) are a group of rare and varied tumors that lack standardized guidelines for their management. Apocrine carcinoma (AC) is a highly uncommon form of breast malignancy, contributing to less than 1 % of all female invasive breast carcinomas. AC has a similar microscopic growth pattern to invasive ductal carcinoma, which can result in early misdiagnosis. PRESENTATION OF CASE: This report presents a case of a 67-year-old female with a lump in the superior lateral quadrant of her left breast for six years. Surgical therapy was performed with wide excision due to clinical operability, no significant involvement of the axillary lymph nodes, and without metatasis. During the operation, Wide excision of 1-2 cm free margin according to standard and local reconstruction flaps were performed, with berry packing for the identified lymph nodes. DISCUSSION: The tumor was ER and PR negative, so hormonal treatment would be ineffective, assuming that this is an apocrine carcinoma of the breast. A metastatic work up was already done, and no metastasis was found. A mastectomy would appear to be a viable option. CONCLUSION: It is important to perform a clinical reevaluation to provide optimal treatment for breast malignancy. Misdiagnosis can occur early. In this case, a surgical procedure involving wide excision was performed, and as of now, the patient has not reported any recurrence.

Vulvar Complex Apocrine Carcinoma in a Horse (Equus caballus): A Case Report and Review of Literature.

A 6-year-old Marwari mare presented with recurrent vulvar growth. The growth was surgically excised, fixed and processed routinely. Microscopically, neoplasm showed proliferation of epithelial and myoepithelial cells with tubulopapillary pattern. On immunohistochemistry, myoepithelial cells showed strong immunoreactivity with smooth muscle actin alpha and p63. On basis of histopathology and immunohistochemistry, tumour was diagnosed as complex apocrine carcinoma. This case report describes first confirm vulvar complex apocrine carcinoma in equines.

Triple-Negative Apocrine Carcinomas: Toward a Unified Group With Shared Molecular Features and Clinical Behavior.

Triple-negative apocrine carcinomas (TNACs) are rare breast tumors with limited studies evaluating their molecular characteristics and clinical behavior. We performed a histologic, immunohistochemical, genetic, and clinicopathologic assessment of 42 invasive TNACs (1 with a focal spindle cell component) from 41 patients, 2 pure apocrine ductal carcinomas in situ (A-DCIS), and 1 A-DCIS associated with spindle cell metaplastic carcinoma (SCMBC). All TNACs had characteristic apocrine morphology and expressed androgen receptor (42/42), gross cystic disease fluid protein 15 (24/24), and CK5/6 (16/16). GATA3 was positive in most cases (16/18, 89%), and SOX10 was negative (0/22). TRPS1 was weakly expressed in a minority of tumors (3/14, 21%). Most TNACs had low Ki67 proliferation (≤10% in 67%, 26/39), with a median index of 10%. Levels of tumor infiltrating lymphocytes were low (≤10% in 93%, 39/42, and 15% in 7%, 3/42). Eighteen percent of TNACs presented with axillary nodal metastasis (7/38). No patients treated with neoadjuvant chemotherapy achieved pathologic complete response (0%, 0/10). Nearly all patients with TNAC (97%, n = 32) were without evidence of disease at the time of study (mean follow-up of 62 months). Seventeen invasive TNACs and 10 A-DCIS (7 with paired invasive TNAC) were profiled by targeted capture-based next-generation DNA sequencing. Pathogenic mutations in phosphatidylinositol 3-kinase pathway genes PIK3CA (53%) and/or PIK3R1 (53%) were identified in all TNACs (100%), including 4 (24%) with comutated PTEN. Ras-MAPK pathway genes, including NF1 (24%), and TP53 were mutated in 6 tumors each (35%). All A-DCIS shared mutations, such as phosphatidylinositol 3-kinase aberrations and copy number alterations with paired invasive TNACs or SCMBC, and a subset of invasive carcinomas showed additional mutations in tumor suppressors (NF1, TP53, ARID2, and CDKN2A). Divergent genetic profiles between A-DCIS and invasive carcinoma were identified in 1 case. In summary, our findings support TNAC as a morphologically, immunohistochemically, and genetically homogeneous subgroup of triple-negative breast carcinomas and suggest overall favorable clinical behavior.

Reappraisal and literature review of primary cutaneous cribriform apocrine carcinoma.

Primary cutaneous cribriform apocrine carcinoma (PCCAC) is an exceedingly rare sweat gland carcinoma. Clinically, it most often presents as a singular, asymptomatic nodule or cyst on the extremities of middle-aged patients and follows an indolent course. Both visceral and cutaneous cribriform tumors exist in nature. While a cribriform pattern is well recognized in tumors of visceral organs, there is a paucity in the literature on the defining characteristics for primary cutaneous tumors. Consensus regarding diagnostic criteria, etiology, and management protocols has yet to be achieved. We conducted an extensive literature review using pre-determined search criteria, resulting in 12 identified case reports and series on PCCAC that were subsequently analyzed. All data were compiled to provide a comprehensive update on the existing information regarding clinical presentation, histopathology, and management of reported PCCACs, as well as differential diagnosis, controversial issues, and recommendations for future considerations.

Role of Volumetric Modulated Arc Technique Radiotherapy in a Rare Case of Intraductal Apocrine Carcinoma of Parotid Gland.

Introduction Apocrine carcinoma, a cancer of sweat glands, is very rare, with a global incidence of 0.0049 to 0.0173 cases per 100,000 persons annually. It is usually found in axilla and anogenital areas. The intraductal apocrine variety of salivary duct carcinoma in the parotid gland is very rare and aggressive and may be due to ectopic sweat glands in the parotid gland duct or metaplastic change of the salivary duct epithelium. It usually presents in an advanced stage. Even though surgery is the standard of care in most head and neck cancers, there are no standard guidelines for the treatment of intraductal apocrine parotid carcinoma, which is different from other head and neck cancers due to its rare incidence, aggressive behavior, and poor prognosis. Case presentation We present a rare case of intraductal apocrine salivary duct carcinoma of the left parotid gland, presented in a locally advanced stage with very high chances of recurrence after surgery, and discuss the role of volumetric modulated arc technique radiotherapy in its management. Conclusion Intraductal apocrine salivary duct carcinoma usually has androgen receptor expression, and lack of expression is associated poor prognosis. Even with complete resection, it has a high recurrence rate. Volumetric modulated arc technique radiotherapy (VMAT) decreases recurrence and increases survival by irradiating the areas more likely of recurrence, with minimal toxicity to surrounding normal tissues.

Tumor-infiltrating lymphocytes status, programmed death-ligand 1 expression, and clinicopathological features of 41 cases of pure apocrine carcinoma of the breast: a retrospective study based on clinical pathological analysis and different immune statuses.

Background: Pure apocrine carcinoma (AC) of the breast can be divided into human epidermal growth factor receptor-2 (HER2)-positive and triple-negative apocrine carcinoma (TNAC). Some studies showed that triple negative breast cancer with low tumor-infiltrating lymphocytes (TILs) and high programmed death-ligand 1 (PD-L1) status may be a therapeutic target for immune checkpoint inhibitors. However, the clinicopathological features of different HER2 expression, TILs status and PD-L1 expression in AC are not clear. Therefore, we investigate the status of TILs and PD-L1, as well as the clinicopathological features of pure apocrine carcinoma of the breast. Methods: We retrospectively analyzed the clinicopathological data, and prognosis of 41 cases of pure apocrine carcinoma of the breast that underwent surgical resection from January 2014 to November 2020. TILs were evaluated. Immunohistochemistry (IHC) staining was applied to detect PD-L1 protein expression in 14 of these samples from January 2019 to November 2020. The expression and correlation of HER2, TILs, PD-L1 and clinicopathological features and prognoses were analyzed. Results: A total of 80.5% (33/41) of patients had TILs <50%, and 19.5% (8/41) had TILs ≥50%. The expression of TILs and the Ki-67 proliferation index were significantly higher in the HER2-positive group (41.5%, 17/41) compared to the HER2-negative group (58.5%, 24/41) (P<0.05). Approximately 52.9% (9/17) of HER2-positive patients treated with Trastuzumab targeted therapy, overall survival was higher in HER2-positive patients than in HER2-negative patients (P=0.211). The PD-L1 positivity rate was 50% (7/14) in the 14 pure apocrine carcinoma of the breast samples, and 66.7% (4/6) and 37.5% (3/8) in the HER2-negative and HER2-positive groups, respectively, with no significant difference (P=0.592). Among these 14 cases, two samples had TILs ≥50%, both of which were positive for PD-L1 and Ki67 >20%; and 12 cases had TILs <50%, of which 41.7% (5/12) were PD-L1-positive and 58.3% (7/12) were PD-L1-negative. All 14 cases with PD-L1-negative had TILs <50%. There was no significant difference in overall survival between TILs and Ki67 co-expression (P=0.452). Conclusions: Pure AC HER2-positive patients have higher levels of TILs and Ki67, HER2 negative and TILs ≥50% patients may have higher PD-L1 expression, which may be helpful for screening patients with different immune statuses to guide effective clinical treatment combinations.

A Case Report on Apocrine Encapsulated Papillary Carcinoma of the Breast with Frank Invasion: A Diagnostic Quandary.

Encapsulated papillary carcinoma is a special type of breast cancer defined in the fifth edition of the World Health Organization breast tumor classification guidelines. Apocrine encapsulated papillary carcinoma is extremely rare, and only 10 cases have been described previously. We encountered a case of apocrine encapsulated papillary carcinoma with frank invasion. The patient was a 77-year-old woman with a painless mass in her right breast. Core needle biopsy revealed that the tumor cells had voluminous eosinophilic cytoplasm and enlarged nuclei with prominent nucleoli. We diagnosed this lesion as carcinoma with apocrine differentiation and suggested the possibility of an encapsulated papillary carcinoma. The patient underwent a right-sided mastectomy. Gross examination of the resected specimen revealed a multilobulated tumor. Microscopically, the tumor cells, which had voluminous eosinophilic cytoplasm and enlarged nuclei with prominent nucleoli, proliferated in papillary fashion with fibrous stalks in the cystic space. Myoepithelial cells were not observed around the cystic space. Frank invasion was also observed around the encapsulated papillary carcinoma. Immunohistochemistry analysis revealed that the tumor cells were negative for estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 and positive for androgen receptor and gross cys-tic disease fluid protein 15. Based on these findings, we diagnosed this lesion as an apocrine encapsulated papillary carcinoma with frank invasion.

Malignant granular cell tumors: Combining cytological and pathological findings for a definitive diagnosis.

Malignant granular cell tumors (GCTs) account for less than 2% of all GCTs and mainly occur in the deep soft tissue of the thigh or trunk. Malignant GCTs are highly aggressive tumors with high rates of recurrence and metastasis. In this brief report, we describe a rare case of malignant GCT in a 64-year-old Japanese man who presented with a 14 × 20 cm mass in the left inguinal region. The cytologic findings of fine-needle aspiration (FNA) revealed atypical epithelial-like granular cells with granular substance in the background, which was difficult to differentiate from apocrine carcinoma or melanoma. The immunohistochemistry (IHC) findings of the needle biopsy revealed that the tumor cells were positive for S-100 and lysosomal marker CD68 which was suggestive of a GCT. However, the presence of crush artifacts made it challenging to identify cellular atypia, which is a characteristic of malignant tumor. Taken together, the FNA and needle biopsy results were suggestive of malignant GCT. The importance of preoperative diagnosis of malignant GCT is well known, but few reports have described its cytological findings. In our brief report, we show that combining cytological FNA and biopsy findings with IHC findings achieves an accurate diagnosis of malignant GCT.

Triple-Negative Apocrine Breast Carcinoma Has Better Prognosis despite Poor Response to Neoadjuvant Chemotherapy.

Apocrine carcinoma is a rare subtype of invasive ductal breast cancer that shows apocrine differentiation and largely triple-negative immunohistology. Triple-negative breast cancers are known to have more aggressive clinical courses. However, unlike most other subtypes, it is reported that triple-negative apocrine carcinoma (TNAC) has a better prognosis. Due to the scarcity of reported studies, our knowledge regarding its clinical behavior, prognosis and response to therapy is very limited. In this study, we retrospectively retrieved 41 triple-negative apocrine carcinoma cases from our breast cancer database, with an average follow-up of 32.8 months. It was found that TNAC had a poorer response to neoadjuvant therapy but a better prognosis than other nonapocrine types of triple-negative breast cancer. Meanwhile, TNAC has a low proliferative nature, as indicated by its low Ki-67 index. An updated analysis of the Surveillance, Epidemiology, and End Results database showed that chemotherapy did not improve breast-cancer-specific survival in TNAC patients. Our results suggest that TNAC is a special subtype of triple-negative breast cancer with a better short-term prognosis despite poor response to neoadjuvant chemotherapy.