So-Woon Kim

Immunohistochemistry for Pathologists: Protocols, Pitfalls, and Tips

Immunohistochemistry (IHC) is an important auxiliary method for pathologists in routine diagnostic work as well as in basic and clinical research including exploration of biomarkers, as IHC allows confirmation of target molecule expressions in the context of microenvironment. Although there has been a considerable progress in automation and standardization of IHC, there are still many things to be considered in proper optimization and appropriate interpretation. In this review, we aim to provide possible pitfalls and useful tips for practicing pathologists and residents in pathology training. First, general procedure of IHC is summarized, followed by pitfalls and tips in each step and a summary of troubleshooting. Second, ways to an accurate interpretation of IHC are discussed, with introduction to general quantification and analysis methods. This review is not intended to provide complete information on IHC, but to be used as a basic reference for practice and publication.

Routine endoscopic screening for synchronous esophageal neoplasm in patients with head and neck squamous cell carcinoma: a prospective study

Early detection of synchronous esophageal squamous cell neoplasm (ESCN) in head and neck squamous cell carcinoma (HNSCC) patients can significantly affect their prognosis. We investigated the prevalence of synchronous ESCN and the risk factors for developing ESCN in patients with HNSCC, and evaluated the effect of routine endoscopic screening in these patients. Subjects who were diagnosed as HNSCC from May 2010 to January 2014 were eligible. All patients underwent conventional white light endoscopic examinations with narrow band imaging and Lugol chromoendoscopy. Among 458 subjects screened, 28 synchronous ESCN were detected in 24 patients (5.2%). The prevalence of ESCN was greatest in patients with hypopharyngeal cancer (20.9%). In multivariate analysis, pyriform sinus involvement was independent risk factor for developing synchronous ESCN (odds ratio 171.2, P < 0.001). During the follow-up period (median, 24 months), the 3-year overall survival rates was significantly lower in patients with ESCN than in patients without ESCN (54.2% vs. 78.3%, P = 0.0013). Routine endoscopic screening for detecting synchronous ESCN should be recommended for patients with HNSCC, especially those with pyriform sinus involvement.

Indeterminate Dendritic Cell Tumor: A Case Report of a Rare Langerhans Cell Lineage Disease

Indeterminate dendritic cell tumor (IDCT) is a very rare neoplastic disorder composed of so-called indeterminate cells [1]. Although it was first described in the early 1980s [2], its pathogenesis and cellular origin have not been completely defined. These indeterminate cells morphologically and immunophenotypically resemble Langerhans cells, as they are immunopositive for S100 protein and CD1a. However, they typically lack both Birbeck granules and langerin expression [1,3]. n nDue to its rarity and similarity to Langerhans cell lesions (LCL), IDCT can be misdiagnosed; however, the pathobiology of IDCT is different from that of LCL. Even though the clinical behavior of IDCT has not yet been firmly established, no direct mortality due to IDCT has been reported so far [1,4]. Recently, we experienced a case of IDCT with typical histologic features. This is the first reported case of IDCT in Korea, which pathologists should include in the differential diagnosis of Langerhans cell-like lesions.

Pancreatic serous cystic neoplasms accompanying other pancreatic tumors

Serous cystic neoplasms (SCNs) are benign cystic neoplasms that predominantly occur in the tail of the pancreas in elderly women. It is well known that patients with von Hippel-Lindau syndrome can develop SCNs and neuroendocrine tumors in the pancreas. However, our understanding on SCNs accompanying other pancreatic tumors (SCNAOPTs) is limited. We compared the clinicopathological features of 15 surgically resected SCNAOPTs with 259 conventional SCNs. The prevalence of SCNAOPT was 5%. The SCNAOPTs were significantly smaller than conventional solitary SCNs, and they were more commonly observed in the head of the pancreas, whereas conventional solitary SCNs were more frequently noted in the body and tail. However, no differences were found in terms of sex, patient age, or the gross patterns of the SCNs. Accompanying neoplasms included 7 intraductal papillary mucinous neoplasms, 1 colloid carcinoma arising from intraductal papillary mucinous neoplasm, 6 neuroendocrine tumors, and 1 solid pseudopapillary neoplasm. Four neuroendocrine tumors associated with von Hippel-Lindau syndrome occurred as multiples, whereas 2 neuroendocrine tumors without von Hippel-Lindau syndrome were solitary. In summary, SCNAOPTs comprise 5% of all SCNs and tend to be smaller and located in the head of the pancreas. Common accompanying tumors include intraductal papillary mucinous neoplasms, neuroendocrine tumors, and other neoplasms such as colloid carcinoma and solid pseudopapillary neoplasm.

Clear Cell Papulosis: A Case Report

Clear cell papulosis (CCP) is an extremely rare entity, as only about two dozen cases have been reported to date in the English literature [1]. In CCP, white papules arise and cluster bilaterally along the mammary line, usually over the lower abdomen and pubis [2]. There is a predisposition for persons of Asian or Hispanic descents and most cases have been found in healthy children younger than 6 years old [1,3]. Typically, the lesions spontaneously resolve with age [4]. Microscopically, the lesions are composed of aberrant cells derived from sweat gland epithelial cells that grow in a pagetoid pattern in the epidermis [2]. CCP provides evidence for the potential precursor cells for cutaneous Paget’s disease [5]. Pathologists should include CCP in the differential diagnosis of whitish maculopapular lesions in the mammary line.

Primary malignant melanoma of the small intestine: a report of 2 cases and a review of the literature.

The majority of malignant melanomas in the small intestine are metastases from primary cutaneous lesions, it can also develop as a primary mucosal tumor in the gastrointestinal tract. In this report, we present rare cases of primary small bowel melanoma and review the current literature. A 78-year-old male presented with abdominal pain and CT enterography identified a ileal mass. A 79-year-old female presented with signs and symptoms of partial small bowel obstruction. Abdominopelvic CT and small bowel series revealed a obstructing mass in the distal jejunum. The masses were confirmed on laparotomy and histologically diagnosed as melanoma. Extensive postoperative clinical examination revealed no cutaneous lesions. A primary small bowel melanoma is an extremely rare neoplasm. A definite diagnosis can only be made after a thorough investigation has been made to exclude the coexistence of a primary lesion. Curative resection of the tumor remains the treatment of choice.

Diagnostic Trends and Clinical Characteristics of Eosinophilic Esophagitis: A Korean, Single-center Database Study

Background/Aims The prevalence of eosinophilic esophagitis (EoE) is reportedly increasing in Western countries. However, its prevalence in Korea remains unknown. We investigated the diagnostic trends and clinical characteristics of EoE in Korea. Methods Using an endoscopic database maintained at a tertiary care center, we retrospectively reviewed the biopsy reports regarding 18 399 biopsy specimens collected from all patients who underwent esophagogastroduodenoscopy and esophageal biopsy at this facility between 2006 and 2014. The presence of more than 15 eosinophils per high-power field with symptoms related to esophageal dysfunction was considered to indicate EoE. Results A total of 37 patients (male:female ratio, 29:8; mean age, 44.0 ± 13.0 years) were diagnosed with EoE. These patients presented with dysphagia (21.6%), epigastric pain (21.6%), heartburn (24.3%), and other symptoms (32.4%). Typical endoscopic appearance of EoE was noted in 33 cases (89.1%) and included linear furrows in 24 cases (64.8%), ringed esophagus in 10 cases (27.0%), and white exudates in 11 cases (29.7%). The median eosinophilic count was 25 per high-power field (interquartile range, 20–70). Notable histopathological findings included eosinophilic microabscesses in 21 cases (56.7%). The diagnosis rate of EoE was found to have increased from 2006 and to 2014 (P-value < 0.001 by the Cochran-Armitage trend test). Conclusions The number of patients with EoE appears to have increased significantly over the 9-year period investigated, while the number of endoscopic investigations increased only marginally. Greater awareness of EoE and the role of esophageal biopsies should be considered.

JOURNAL CLUB: Primary Anorectal Melanoma: MRI Findings and Clinicopathologic Correlations

OBJECTIVEnThe purpose of this study is to evaluate the MRI features of primary anorectal malignant melanoma and to correlate these features with its clinical and pathologic characteristics.nnnMATERIALS AND METHODSnThe medical records of 12 patients (five men and seven women; mean age [± SD], 60.8 ± 10.0 years) with pathologically proven primary anorectal melanoma were retrospectively reviewed. MRI findings were analyzed to determine the shape, size, distance from the anal verge, presence of perirectal or anal infiltration, signal intensity on T1- and T2-weighted images, presence of diffusion restriction, contrast enhancement pattern of the lesion, presence of lymphadenopathy, and occurrence of bowel obstruction. Subsequent follow-up data for the patients were recorded.nnnRESULTSnThe most common presentation was hematochezia (41.7% of patients). Common findings on MRI included a large intraluminal polypoid mass (75.0% of lesions) with little perirectal or anal infiltration (100.0%), T1 hyperintensity (66.7%), high T2 signal intensity (54.5%) or mixed T2 signal intensity (45.5%), restricted diffusion (100.0%), and hyper-enhancement (100.0%). The mean length, width, and depth of these masses were 3.5, 2.9, and 2.3 cm, respectively. The mean distance from the anal verge was 1.8 cm. Lymphadenopathy was frequently identified (75.0% of cases), with lymph nodes larger than 2 cm noted in 28.5% of cases and most commonly involving the perirectal area (77.8% of cases). No colonic obstructions were observed. The mean patient follow-up was 32.7 months. A total of 25.0% of patients died as a result of disease progression.nnnCONCLUSIONnThe possibility of the presence of anorectal melanoma should be considered for patients with a bulky intraluminal polypoid mass in the anorectum without colonic obstruction, with the mass showing T1 hyperintensity, high or mixed signal T2 intensity, hyperenhancement, minimal perirectal or anal infiltration, and lymphadenopathy.

Hepatocellular Carcinoma Arising in a Huge Hepatocellular Adenoma with Bone Marrow Metaplasia

Hepatocellular adenoma (HCA) is the most common type of benign liver tumor, and its major complication is malignant transformation to hepatocellular carcinoma (HCC). Here, we report a case of HCC arising in HCA with bone marrow metaplasia in a 24-year-old Korean woman who presented with abdominal discomfort. A huge liver mass was found on abdominal ultrasonography. She underwent surgical hepatic resection, and the resected specimen was entirely involved by a 20-cm-sized tumor. Histological review revealed a well differentiated HCC arising from inflammatory HCA with β-catenin nuclear positivity and bone marrow metaplasia that contained hematopoietic cells. This case was unique because malignant transformation, inflammatory type HCA, β-catenin nuclear staining, and bone marrow metaplasia were simultaneously observed. Additionally, it should be noted that a large HCA with β-catenin activation can undergo malignant transformation and should be surgically resected in a timely manner.