History 58 year-old female presented with back pain and right toe numbness. Her past medical history was significant for hypertension, glaucoma and morbid obesity Her past surgical history was significant for remote cholecystectomy After outpatient evaluation by neurosurgery, an MRI of her spine was obtained

Describe the findings on the MRI imaging

Answer: Destructive soft tissue mass centered at the lamina and spinous process of L5 which appears to measure in aggregate 3.8 x 3.6 x 3 cm. The patient was scheduled for a biopsy

Describe this low-power view from the smear preparation.

Answer Tissue fragments and small clumps of cells Cellular smear Tissue fragments and small clumps of cells Specimen appears lesional

Describe the high-power cytologic features from the smear

Answer Acinar formation Abundant eosinophilic cytoplasm Cohesive cells clusters Intra-nuclear inclusions

Question: Is the lesional tissue neoplastic?

Answer Yes; and most likely a metastatic neoplasm. However due to the lack of any known primary tumor in this patient a final diagnosis can only be made on the permanent sections.

Question 2: What other stains would be useful to make an accurate diagnosis of this lesion?

Describe the histologic findings on the permanent H&E section

Answer Vaguely nodular and cellular lesion

Describe this high-power area

Answer: Similar to the smear preparation: Cells forming acini-pseudoglands Abundant granular eosinophilic cytoplasm Round nuclei with coarse chromatin Intranuclear inclusions

Describe this other H&E high-power field

Answer This field shows marked steatosis in many of the neoplastic cells

By this time we are informed that her AFP level was 13422 ng/mL (normal range is <20)

Question Based on the morphologic features and clinical presentation, what is the most likely diagnosis?

Answer Metastatic hepatocellular carcinoma (HCC)

Question: What stains would you do to confirm metastatic HCC

Answer HCC typically have this immunoprofile CK7 – CK20 – HepPar + AFP + A1-antitrypsin + CEA +

Immunohistochemical stains CK7 CK20

A1-AT AFP CEA HepPar1

Are you convinced? YES!