ALK-rearranged adenocarcinoma with extensive mucin production can mimic mucinous adenocarcinoma: clinicopathological analysis and comprehensive histological comparison with KRAS-mutated mucinous adenocarcinoma.
We aimed to investigate clinicopathological features and histology of ALK-rearranged adenocarcinomas with extensive mucin production (AEM) that mimic mucinous adenocarcinoma (MA). Retrospectively, 12 cases of AEM and 25 cases of MA harbouring KRAS mutation were retrieved. The clinicopathological profile and detailed histological features were analysed and compared based on the ALK and KRAS status. AEMs occurred in younger patients (p = 0.044) and were characterised by floating tubulopapillary pattern (p < 0.001), prominent nucleolus (p < 0.001), and apical cytoplasmic snouts (p < 0.001). In contrast, KRAS-mutated MAs lacked ALK-specific histological patterns (p < 0.05). Instead, tumour-infiltrating leukocytes (p = 0.018) and smooth cytoplasmic borders (p < 0.001) with vesicular nuclei (p = 0.004) were prominent in KRAS-mutated MAs. AEMs demonstrated characteristic tubulopapillary pattern and apical snouts, which were distinguishing features from MAs with KRAS mutation. Apical snouts can be a useful histological surrogate for ALK rearrangement in the pulmonary adenocarcinomas showing extensive mucin that mimic MA.
Department of Pathology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea; Department of Pathology, Yonsei University College of Medicine, Seoul, South Korea.
Yoon Jin
YJ
Cha
Department of Pathology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea. Electronic address: hanjho@skku.edu.
Joungho
J
Han
Department of Pathology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.
Soo Hyun
SH
Hwang
Department of Pathology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.
Tae Bum
TB
Lee
Division of Pulmonary and Critical Care Medicine, Seoul, South Korea.
Hojoong
H
Kim
Thoracic Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.
Jea Ill
JI
Zo
D000230:Adenocarcinoma / Q000175:diagnosis* / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D002288:Adenocarcinoma, Mucinous / Q000175:diagnosis* / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D000328:Adult; D000367:Age Factors; D000368:Aged; D000077548:Anaplastic Lymphoma Kinase; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009077:Mucins / Q000378:metabolism*; D009154:Mutation; D016283:Proto-Oncogene Proteins p21(ras) / Q000235:genetics* / Q000378:metabolism; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics* / Q000378:metabolism; D012189:Retrospective Studies
C117307:KRAS protein, human; D009077:Mucins; C000626173:ALK protein, human; D000077548:Anaplastic Lymphoma Kinase; D020794:Receptor Protein-Tyrosine Kinases; D016283:Proto-Oncogene Proteins p21(ras)
Adenocarcinoma of lung; adenocarcinoma; anaplastic lymphoma kinase; histology; mucinous