Here is a selection of new images from our free, online textbook:

CNS tumor > Papillary craniopharyngioma
Classic low power cauliflower-like configuration with smooth borders.
Contributed by Nelli S. Lakis M.D., M.Sc.

Nasal cavity, paranasal sinuses, nasopharynx > Sinonasal undifferentiated carcinoma
Sheets of undifferentiated malignant epithelial cells with vesicular nuclear chromatin and prominent nucleoli.
Contributed by Bin Xu, M.D., Ph.D. and Abeer Salama, M.D.

Placenta > Choriocarcinoma
Intraplacental choriocarcinoma showing atypical syncytiotrophoblast, cytotrophoblast and intermediate trophoblast adjacent to uninvolved chorionic villi (H&E, 200x).
Contributed by Tatyana Zinger, D.O.

Small intestine & ampulla > Heterotopic gastric mucosa
Polypoid lesion predominantly lined by gastric foveolar epithelium and small intestinal epithelium on the left side.
Contributed by Khalid Amin, M.D.

Liver & intrahepatic bile ducts > Hepatocellular adenoma
HNF1A mutated hepatocellular adenoma: low power view showing well defined border between the lesion (right) and background liver (left).
Contributed by Monica Abdelmalak, M.D.