This gastric "enteroblastic" carcinoma expressed germ cell tumor markers but is somatically derived. It seems that only isochrome 12p (i[12p]) unequivocally identifies true germ cell tumors! However, we can usually sort it out on clinical grounds.
https://t.co/Xc5QHP9nuH
Bread and butter! Detached (dissected, sloughed) superficial epithelium in
esophagitis dissecans/sloughing esophagitis loses glycogen. Basal epithelium normally lacks it. Esophagitis dissecans is usually self-limited, but this example has associated eosinophilic esophagitis.
Vascular malformations, particularly when associated with disfigurement, are worth sequencing, for both diagnostic refinement and the search for actionable alterations.
https://t.co/mumQnlhofO
Primary perianal adenocarcinoma with pagetoid intra-epithelial extension - these look a bit like HPV-associated lesions, lack HPV transcripts, and have TP53, ERBB2, and MYC abnormalities, without typical rectal adenocarcinoma mutations (APC, KRAS, BRAF). https://t.co/ajb2kPFkBI
Just a bread and butter case: with better control of HIV disease it is easy to forget about Kaposi sarcoma - this example with hyaline globules. (erythrophagolysosomes).
This is a subcutaneous pleomorphic liposarcoma. It looks like a "generic" high-grade pleomorphic sarcoma until the pleomorphic lipoblasts are spotted. They may be in a spectrum with the more recently described myxoid pleomorphic liposarcoma.
https://t.co/LIMFLKJMyk
Langerhans cell histiocytosis (LCH) can present as colorectal polyps in adults and is generally indolent - analogous to to eosinophilic granuloma. Pediatric gastrointestinal LCH, in contrast, is often devastating.
https://t.co/6biwBF7EfC
Once in a while, squamous carcinomas are associated with low-risk human papillomavirus (HPV). Vulvovaginal examples seem to have their own special molecular signature; this well-differentiated example arose in the anal canal - fewer data are available.
https://t.co/ulQqkIPhiW
The names have changed for this goblet cell adenocarcinoma, but not the molecular findings. In the past this lesion was a "goblet cell carcinoid" and high grade examples were "adenocarcinoma ex goblet cell carcinoid". Check out this vintage article.
https://t.co/dF7BsLJ33i
This mammary myofibroblastoma arose in a man's breast (this lesion is more common in men than women). It co-expressed desmin and CD34; Rb protein loss would be anticipated! Good bread and butter!
Years ago, colleagues noted that paraganglia (NOT paragangliomas) can mimic prostate adenocarcinoma on prostate needle biopsies. In the gallbladder, the issue would be a neuroendocrine tumor!
https://t.co/jBUCtMGVaM
Checkpoint inhibitor therapy (with nivolumab in this case)-associated injury sometimes mimics traditional immune disease states. The apoptotic keratinocytes damaged by lymphocytes (arrow; Civatte bodies) and lymphocytosis mimic esophageal lichen planus.
https://t.co/50IUvRpanp
Some hepatic adenomas are easy - this one is beta catenin activated and thus should be resected. An endothelial cell (negative internal control, arrow) shows no nuclear staining. Note the unpaired artery. However, Mod Pathol offers some tips!
https://t.co/tuPIPko1QU
The arrows demonstrate hyaline globules (erythrophagolysosomes), the diagnostic clue for pathologists who can diagnose it perfectly well without immunohistochemistry.
Most evidence to date tells us that Kaposi sarcoma (a gastric example is shown) shows differentiation along lymphatic lines, but the spatial relationship between the lesional cells and the company that they keep proves fascinating. https://t.co/LKxh1lKWqx
Most evidence to date tells us that Kaposi sarcoma (a gastric example is shown) shows differentiation along lymphatic lines, but the spatial relationship between the lesional cells and the company that they keep proves fascinating. https://t.co/LKxh1lKWqx
The number of times we have diagnosed a GI tract mast cell disorder (systemic mastocytosis seen here) because we spotted it on H&E - quite a few. The number of times we have diagnosed a mast cell disorder because we were asked to do silly stains? ZERO. https://t.co/32VK7yizIn
A striking peritoneal mesothelioma that resulted in small bowel obstruction. Nuclear grading can offer prognostic information! Read all about it in Modern Pathology: https://t.co/riaayCdlkp