UNASSIGNED: 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.
UNASSIGNED: 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.
UNASSIGNED: Invasive SPC of the male breast may occur as a palpable mass or nipple discharge in older men and has a good prognosis.

BACKGROUND: Both hepatoid adenocarcinoma of the stomach (HAS) and neuroendocrine differentiation (NED) are rare histological subtypes of gastric cancer with unique clinicopathological features and unfavorable outcomes. HAS with NED is even rarer.
METHODS: Here, we report a 61-year-old man with HAS with NED, as detected by gastric wall thickening by positron emission tomography/computed tomography for a pulmonary nodule. Distal gastrectomy was performed, and pathological examination led to the diagnosis of HAS with NED. However, liver metastases occurred 6 mo later despite adjuvant chemotherapy, and the patient died 27 mo postoperatively.
CONCLUSIONS: We treated a patient with HAS with NED who underwent adjuvant chemotherapy after radical surgery and still developed liver metastases. We first report the detailed processes of the treatment and development of HAS with NED, providing an important reference for the clinical diagnosis and treatment of this condition.

Extramammary Paget\'s disease (EMPD) is a rare cutaneous neoplasm with distant metastases and a poor prognosis. We report the case of a 63-year-old male patient exhibiting stage IV primary EMPD with neuroendocrine differentiation, and harboring a somatic mutation in AMER1. After four cycles of Anlotinib combined with Tislelizumab, the patient achieved partial response for the metastatic lesions according to mRECIST1.1 criteria. Total positron emission tomography and computed tomography (PET-CT) scans revealed a significant reduction in SUV from 18.9 to 5.3, and the serum CEA decreased to normal levels after the treatment regimen. However, the patient developed fractures of the fourth and fifth thoracic vertebrae during the treatment. Therefore, percutaneous vertebroplasty was performed, and the patient experienced severe postoperative pneumonia and died from pulmonary encephalopathy and respiratory failure in June 2021. The overall and progression-free survival of the patient after diagnosis were 9 and 8 months, respectively. During the systemic treatment, the patient suffered grade 1 rash in the back and thigh and grade 1 hypertension. Nevertheless, the combination treatment of anlotinib and tislelizumab had a favorable clinical outcome and provided a survival advantage, and should be considered a therapeutic option for patients with AMER1-mutant metastatic EMPD.

Metastatic malignant melanoma (MM) represents a highly aggressive cancer associated with overall poor prognosis. Various anatomic sites can be affected, including the oral cavity and the oropharynx. It may mimic other entities by assuming a variety of clinical appearances and exhibiting a plethora of microscopic variations. Herein, we present a case of a 63-year-old male with a MM metastasizing to the base of tongue, which developed 5 years after the original diagnosis and treatment of cutaneous MM of the chest and heralded its relapse; subsequently, neurological symptoms developed as a result of metastasis to the brain. Diagnostic challenges were encountered, as the tongue lesion clinically masqueraded as a pedunculated reactive lesion and microscopically displayed unusual rhabdoid and neuroendocrine features. Tumor cells expressed S-100, HMB-45, Melan-A, and SOX-10, while most cells with rhabdoid morphology were also positive for myogenin and Myo-D1. Chromogranin and synaptophysin positivity was further noticed in a subset of cells, suggestive of focal neuroendocrine differentiation. Molecular investigation revealed mutations for the BRAF V600E gene. Divergent differentiation of tumor cells may cause diagnostic pitfalls necessitating thorough immunohistochemical analysis. The presence of rhabdoid features and neuroendocrine differentiation are very uncommon, while their co-existence is extremely rare. Better characterization of such microscopic variations in MMs with evaluation of their potential biologic significance is warranted.

UNASSIGNED: Neuroendocrine breast carcinoma (NEBC) is a rare subgroup of breast cancer, which makes up 2-5% of all invasive breast cancers. The aim of this retrospective analysis is to present and analyze our own data of primary NEBCs.
UNASSIGNED: We retrospectively analyzed clinical, pathological, and radiological characteristics of 36 patients diagnosed with neuroendocrine differentiated breast cancer between 2008 and 2019 compared to that of 925 patients with invasive ductal carcinoma (IDC/NOS) along with a literature review.
UNASSIGNED: In this study, 36 patients with neuroendocrine differentiated breast carcinoma and 961 patients with (IDC/NOS), as the comparison group, were identified between 2008 and 2019. In NEBC patients, seven were premenopausal and 29 postmenopausal. Patients whose ultrasound (USG), magnetic resonance, and mammographic (MMG) images available in our hospital, high-density masses were detected in the MMG with irregular (77%), microlobulated (80%) and spiculated margins (63%), unaccompanied by asymmetry and structural distortion. Calcifications were less common than invasive breast cancer, present only in four patients (17%). When NEBC were compared to ductal carcinomas (n=925), NEBC were more often human epidermal growth factor receptor 2 negative (p=0.039), estrogen receptor positive (p=0.05), progesterone receptor positive (0.03), and the NEBC patients were older (p=0.02). Age, grade, metastatic status, lymph node number, and molecular type were identified as prognostic factors that significantly affect survival in both groups (p<0.05).
UNASSIGNED: NEBC is a subtype that is both histopathologically and radiologically distinct from other breast cancer subtypes, and neuroendocrine differentiation may be an important predictive marker in the future.

Non-islet cell tumor hypoglycemia (NICTH) is a very rare symptom of severe hypoglycemia associated with extrapancreatic tumors. It is considered to be caused by insulin-like growth factor (IGF)-II. There have been no autopsy cases of colorectal carcinoma with NICTH confirmed with both serum high molecular weight and tumoral IGF-II. We report the case of a 46-year-old woman with advanced sigmoid colon cancer and liver metastases. She underwent open sigmoidectomy, and histologically, the lesion was a differentiated-type tubular adenocarcinoma. Postoperative chemotherapy was initiated. However, she experienced repeated hypoglycemia attacks 10 months after the operation, while the liver metastases increased. We examined the cause of hypoglycemia, and finally diagnosed her with NICTH associated with high molecular weight IGF-II production, which was proven by Western immunoblot of the serum. She died 12 months after surgery and was examined by autopsy. Liver metastases showed a transition from adenocarcinoma to carcinoma with neuroendocrine differentiation. Immunohistochemistry showed that both metastatic carcinoma of the liver and primary colonic adenocarcinoma were positive for IGF-II. Neuroendocrine differentiation in liver metastases proven by an autopsy may have contributed to tumor growth, which may have exacerbated the symptoms.

BACKGROUND: Melanoma has a wide range of histologic variants and cytomorphologic features that make its diagnosis challenging. Melanoma can also rarely have neuroendocrine markers adding further diagnostic uncertainty particularly given that unrelated tumor types, such as prostate cancer, can also display focal neuroendocrine differentiations.
METHODS: Our patient is a 74-year-old Caucasian man found to have a lung mass. Initial biopsy revealed typical microscopic morphology and neuroendocrine differentiation consistent with small cell carcinoma. Despite standard chemoradiation treatment, the patient continued to progress with new metastasis in the brain, liver and bone. Subsequent chest wall biopsy revealed golden-brown pigment associated with melanin. Further tumor immunohistochemistry revealed extensive neuroendocrine differentiation with CD56, synaptophysin, and INSM1, as well as strong immunoreactivity for melanocyte markers including SOX10, S100, PRAME, and MITF, consistent with metastatic melanoma with neuroendocrine differentiation. Genomic testing revealed increased tumor mutational burden and alterations in NF1, BRAF, CDKN2A/B, TERT. The patient was transitioned to checkpoint inhibitor therapy with nivolumab and ipilimumab and had resolution of his intracranial mass and decrease in size of other metastatic lesions.
CONCLUSIONS: Often the combination of anatomic findings such as a lung mass, typical microscopic morphology, and confirmation of neuroendocrine differentiation correctly identifies a patient with small cell carcinoma. However, in a patient who fails to respond to treatment, a broader immunohistochemical workup along with molecular testing with additional tissue may be warranted.

Cutaneous apocrine carcinomas share common features with their counterparts in the breast; hence, metastatic mammary carcinoma must be excluded before such lesions can be designated primary cutaneous neoplasms. Primary tumors from either source rarely exhibit neuroendocrine differentiation. We report a case of a 72-year-old female with a painless 1.2-cm scalp nodule. An incisional biopsy revealed dermal involvement by an invasive apocrine carcinoma juxtaposed to a benign apocrine cystic lesion. Immunohistochemically, the carcinoma expressed neuroendocrine proteins including synaptophysin, chromogranin, and CD56. A primary cutaneous apocrine carcinoma with neuroendocrine differentiation was favored, but additional investigations to exclude breast origin were recommended. These revealed a 1.1-cm nodule in the right breast, which proved to be an invasive ductal carcinoma, morphologically and immunophenotypically similar to the scalp lesion. This confounded the case, yet factors militating against metastatic breast carcinoma to skin included (a) the small size of the mammary tumor, (b) absence of other metastatic disease, and (c) juxtaposition of the scalp carcinoma to a putative benign precursor. Molecular studies were undertaken to resolve the diagnostic quandary. Single nucleotide polymorphism microarray analysis revealed distinct patterns of chromosomal copy number alterations in the two tumors, supporting the concept of synchronous and unusual primary neoplasms.

Androgen receptor signaling primarily influences both the normal growth and proliferation of the prostate gland and the development of prostatic carcinoma. While localized prostate cancers are typically managed with definitive therapies like surgery and radiotherapy, many patients have recurrences in the form of metastatic disease. Androgen deprivation therapy, by way of castration via orchiectomy or with drugs like luteinizing hormone-releasing hormone (commonly called gonadotropin-releasing hormone) agonists and luteinizing hormone-releasing hormone antagonists, is the primary mode of therapy for advanced castration-sensitive prostate cancer. Castration resistance invariably develops in these patients. Further treatment has shifted to newer anti-androgen drugs like enzalutamide or abiraterone and taxane-based chemotherapy. Prolonged inhibition of the androgen receptor signaling pathway causes androgen receptor-independent clonal evolution which leads to the development of treatment-emergent neuroendocrine prostate cancer. All prostate cancers at the initial presentation should undergo evaluation for the markers of neuroendocrine differentiation. Detection of serum biomarkers of neuroendocrine differentiation and circulating tumor cells is a prospective non-invasive method of detecting neuroendocrine transdifferentiation in patients undergoing treatment with androgen receptor pathway inhibitors. It is essential to perform a biopsy in the presence of red flags of neuroendocrine differentiation. Alisertib, an Aurora kinase inhibitor, showed promising clinical benefit in a subgroup of patients with certain molecular alterations. A thorough understanding of the molecular and clinical programming of treatment-emergent neuroendocrine prostate cancer can potentially lead to the development of drugs to prevent the development of this lethal variant of prostate cancer.

Orbital metastases from cancers of various organs can arise via the hematogenous route, and many originate from breast, prostate, and lung cancers. Such metastatic orbital tumors may be diagnosed before the primary tumor. We have encountered a case of breast ductal carcinoma with neuroendocrine differentiation that metastasized to the orbit and responded to chemotherapy, with improvement in visual function.
A woman in her fifties visited our ophthalmology department with a chief complaint of foreign body sensation and exophthalmos in her right eye. An elastic soft mass was palpated from the lateral orbit to the temporal region. A systemic examination revealed breast cancer and a metastatic orbital tumor. Excisional biopsy of the breast revealed a diagnosis of invasive ductal carcinoma with neuroendocrine differentiation, and immunohistochemical examination was negative for cytokeratin 7, making the case unusual. Chemotherapy was remarkably effective, and the tumor size decreased, resulting in improvement of visual function. Her general condition and quality of life are still good at present. We searched the PubMed English language literature focusing on metastatic orbital tumors from breast cancer in which ocular symptoms had been the initial presenting sign. No previous reports have documented neuroendocrine differentiation or cytokeratin 7 expression in isolated orbital metastases from breast cancer. Although it is not possible to be certain from this case alone, we speculated that some such cases might involve cytokeratin 7-negative invasive breast cancer with neuroendocrine differentiation.
We have described our experience of a very rare case of cytokeratin 7 negative breast ductal carcinoma with neuroendocrine differentiation that metastasized to the orbit and formed a solitary giant tumor initially manifesting as ocular symptoms.