The International Agency for Research on Cancer (IARC) published the World Health Organization (WHO) classification of thoracic tumors (5th edition) in May 2021, only six years after the 4th edition of WHO Classification. With the application of low-dose spiral computed tomography (CT) as an early screening method for lung tumors in recent years, lung adenocarcinoma has become the main type of disease in many hospital surgical treatments. The WHO classification serves as the authoritative guide for pathological diagnosis, and any slight change in the classification is at the heart of pathologists, clinicians and patients. Adenocarcinoma in situ is a newly added type of adenocarcinoma diagnosis in the 4th edition of the WHO classification, and it is also the focus of clinical treatment and research at home and abroad in recent years. Because its catalog position has been adjusted in the 5th edition of the WHO classification, there has been a huge controversy and discussion among clinicians and patients that "adenocarcinoma in situ was excluded from the category of malignant tumors". This article will briefly explain the origin of the diagnosis of lung adenocarcinoma in situ, the adjustment of the new classification catalog, and whether adenocarcinoma in situ is benign or malignant.
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Adenocarcinoma in Situ/pathology* ; Adenocarcinoma of Lung/diagnostic imaging* ; Humans ; Lung Neoplasms/pathology* ; Neoplasm Staging

OBJECTIVETo observe and summarize the morphologic features that may suggest submucosal invasive adenocarcinoma in colorectal mucosa biopsy specimens.

METHODSThe study cohort included 432 colorectal biopsy specimens were obtained from 2006 to 2012. All the cases had radical surgery. Basing on the pathologic diagnoses, the cases were divided into 366 invasive adenocarcinoma (IAC) and 66 high-grade intraepithelial neoplasms (HGIN). These two groups were compared.

RESULTSIn the IAC group, the percentage of tumor forming cribriform structures, acute angle-shaped glands, diffuse carcinoma cell proliferation was 61.2% (224/366) , 33.8% (124/366) and 7.4% (27/366) , respectively. In the HGIN group, cribriform gland structures appeared in 6.0% (4/66) of the cases, while no acute angle-shaped gland or diffuse carcinoma cell proliferation was detected. The difference of these three characteristics in the two group was statistically significant (all P < 0.01). Glandular branching was detected in 89.9% (329/366) of IAC cases and 66.7% (44/66) of HGIN cases; this difference was not significant. There was no difference in cellular atypia between the two groups. Interstitial fibrosis was detected more frequently in the IAC group (85.5%, 313/366 in IAC versus 0 in HGIN, P < 0.01). In biopsy specimens of IAC, a few cases showed neoplastic glands in close contact with large lymphatics, adipose tissue, and ganglion.

CONCLUSIONSIn colorectal biopsy specimen, the five features that suggest submucosal invasion of the neoplastic glands including the formation of cribriform structure, angular gland, diffuse carcinoma cells, interstitial fibrosis and neoplastic glands in close contact with the thick-walled vessels.

Adenocarcinoma ; pathology ; Biopsy ; Carcinoma in Situ ; pathology ; Cell Proliferation ; Diagnosis, Differential ; Humans ; Intestinal Mucosa ; pathology ; Neoplasm Invasiveness

Female ; Humans ; Adenocarcinoma in Situ ; Uterine Cervical Neoplasms/pathology* ; Papillomavirus Infections ; Cervix Uteri/pathology* ; Adenocarcinoma/pathology* ; Papillomaviridae ; DNA, Viral

Adenocarcinoma, Clear Cell/pathology* ; Carcinoma in Situ ; Cell Transformation, Neoplastic ; China ; Endometriosis/pathology* ; Female ; Humans

Mucocele-like tumor (MLT) of the breast is a rare neoplasm. Although this lesion was considered benign when first described, the concept of a pathologic continuum with mucinous carcinoma was evident in subsequent reports. Only a few cases of MLT have been reported in Korea. We describe a case of MLT associated with ductal carcinoma in situ and mucinous carcinoma in a 34-yr-old female. Histological examination showed multiple mucus-filled cysts of varying size. Extravasated mucin was present in the surrounding stroma. The lining of the cysts in most areas were of flat or cuboidal epithelium and devoid of cellular atypia. The lining epithelium showed proliferative change ranging from atypical ductal hyperplasia to ductal carcinoma in situ, micropapillary type. A microscopic focus of mucinous carcinoma within MLT was also noted. None of the lesions exhibited epithelial reactivity for p53 protein. The patient is alive and well without evidence of disease 54 months after initial treatment. This case supports the concept that MLT encompasses a spectrum of pathologic lesions including benign tumor, atypical ductal hyperplasia, ductal carcinoma in situ, and mucinous carcinoma.
Adenocarcinoma, Mucinous/*pathology ; Adult ; Breast Neoplasms/*pathology ; Carcinoma in Situ/*pathology ; Carcinoma, Infiltrating Duct/*pathology ; Diagnosis, Differential ; Female ; Human ; Mucocele/*pathology

OBJECTIVETo evaluate the standards of HER2 immunohistochemistry (IHC) interpretation in invasive micropapillary carcinoma of the breast (IMPC).

METHODSHER2 expression in 60 cases of IMPC was evaluated by IHC and fluorescence in situ hybridization (FISH) using TMA-based techniques. The characteristics between cases with HER2 IHC and HER2 gene amplification results were compared.

RESULTSUsing 2007 American Society of Clinical Oncology/College of American Pathologist (ASCO/CAP) criteria, among the 52 cases that were successfully stained by IHC, 40 were HER2 IHC negative and 12 were equivocal (2+). Fifteen cases of HER2 IHC 0 were negative for amplification by FISH. Twenty-five cases with IHC 1+ were tested by FISH; and of these, one showed HER2 amplification, 2 were equivocal, and the others were not amplified. All cases of IHC 2+ showed HER2 amplification by FISH. IHC staining of HER2 was located at cell-cell membrane or basolateral membrane of micropapillary structure, but not in the cytoplasmic membrane facing the stroma in all 13 cases which were HER2 amplified, including 12 showing very strong staining and one showing moderate staining. Among the 37 non amplified HER2 cases, 22 showed IHC staining at cell-cell membrane or basolateral membrane (including 15 weak staining and 7 moderate staining).

CONCLUSIONSHER2 IHC detection in IMPC is characterized by staining at cell-cell membrane or basolateral membrane of the micropapillary structure, and absence of staining in the cytoplasmic membrane. It is suggested that interpretation of HER2 IHC staining should be based on membrane staining intensity, but not the completeness of the membrane staining in IMPC. It is suggested to determine the HER2 gene amplification status by using FISH when IHC staining shows moderate or strong intensity.

Adenocarcinoma, Papillary ; chemistry ; pathology ; Breast Neoplasms ; chemistry ; pathology ; Female ; Humans ; Immunohistochemistry ; In Situ Hybridization, Fluorescence ; Receptor, ErbB-2 ; analysis

Adenocarcinoma ; pathology ; Carcinoma in Situ ; pathology ; Digestive System Neoplasms ; classification ; pathology ; Esophagogastric Junction ; pathology ; Humans ; Liver Neoplasms ; pathology ; Neoplasm Staging ; Neuroendocrine Tumors ; classification ; pathology ; Pancreatic Neoplasms ; pathology ; Precancerous Conditions ; pathology ; World Health Organization

OBJECTIVETo study the clinical and pathological features of mucocele-like lesions in the breast.

METHODSNine cases of mucocele-like lesions in the breast were reported for the morphological and immunohistochemical features, the differential diagnosis, and a literature review.

RESULTSAll nine cases were from female patients, aged 23 to 43 years (mean 34 years), clinically presented with palpable breast masses. Grossly, the lesions were multi-cystic with colloidal appearances. Histologically, the lesions consisted of multiple cysts filled with colloid, these cysts were lined with tubular, cuboidal or columnar epithelium. There were superimposed papillary epithelial hyperplasia in three cases and atypical ductal hyperplasia in one. Extravasated mucinous lakes were seen in the stroma, but without cellular component.

CONCLUSIONMucocele-like lesions of the breast is a group of mostly benign disease, and the differential diagnosis should include mucinous carcinoma.

Adenocarcinoma, Mucinous ; diagnosis ; pathology ; Breast ; pathology ; Breast Neoplasms ; diagnosis ; pathology ; Carcinoma in Situ ; diagnosis ; Carcinoma, Ductal, Breast ; diagnosis ; pathology ; Diagnosis, Differential ; Female ; Gene Expression Regulation, Neoplastic ; physiology ; Humans ; Hyperplasia ; pathology ; Intestinal Neoplasms ; pathology ; Mucocele ; diagnosis ; pathology

Adenocarcinoma ; pathology ; Adult ; Aged ; Carcinoma in Situ ; pathology ; Carcinoma, Squamous Cell ; pathology ; Cervical Intraepithelial Neoplasia ; pathology ; Cervix Uteri ; pathology ; Early Detection of Cancer ; Female ; Humans ; Middle Aged ; Uterine Cervical Dysplasia ; pathology ; Uterine Cervical Neoplasms ; pathology ; Vaginal Smears ; classification ; Young Adult

OBJECTIVETo study the cytomorphologic features of anaplastic lymphoma kinase (ALK)-rearranged pulmonary adenocarcinoma.

METHODSThe morphologic features in 153 pulmonary adenocarcinoma cytology specimens encountered during the period from September, 2011 to April, 2015 in Shanghai Cancer Hospital were retrospectively reviewed. Fluorescence in-situ hybridization (FISH) and/or immunohistochemistry (Ventana D5F3) for ALK gene rearrangement were carried out. The samples studied included 34 pleural effusion specimens, 40 endobronchial ultrasound-guided transbronchial needle aspirates (EBUS-TBNA) and 79 fine needle aspirates of palpable masses on body surface.

RESULTSThirty-nine cases (25.5%) of ALK-rearranged samples were identified by FISH and/or immunohistochemistry, including 3 cases diagnosed by FISH and 36 cases by both technologies. The median age of the ALK-positive group was 50 years, significantly younger than that of the ALK-negative group (60 years old, P = 0.002). Only 4 of the ALK-positive patients were smokers, which was significantly less than that of the ALK-negative group (P < 0.01). In ALK-positive group, 3 cases showed cribriform pattern with prominent nucleoli, 3 cases showed cribriform pattern with mucin-rich cells and 8 cases showed extracellular mucus with mucin-rich cells. The above cytomorphologic patterns were significantly less common in ALK-negative tumors (P < 0.01).

CONCLUSIONSALK-rearranged lung adenocarcinoma is associated with certain distinctive morphologic patterns, including cribriform architecture, presence of prominent nucleoli, mucin-rich cells and extracellular mucus, which can be observed in cytology specimens (including conventional smears and cell block sections). These findings, when combined with clinical features, may give clues to detection of ALK-positive cases.

Adenocarcinoma ; genetics ; pathology ; Biopsy, Fine-Needle ; China ; Gene Rearrangement ; Humans ; Immunohistochemistry ; In Situ Hybridization, Fluorescence ; Lung Neoplasms ; genetics ; pathology ; Receptor Protein-Tyrosine Kinases ; genetics ; Retrospective Studies