Case History

A 50-year-old male presents with a 9 cm retroperitoneal mass who had a resection of 16 cm fatty retroperitoneal mass 10 years prior.

Which of the following will show diffuse positivity in this tumor?

  1.       S100
  2.       SMA
  3.       MDM2
  4.       Desmin

Figure 1 Figure 2 Figure 3 Figure 4

 Case History

A 62-year-old- male with a history of multiple skin cancers presents to an ENT for a newly discovered firm mass adjacent to his right nasal ala. After biopsy, the mass is resected (Fig A-D).

This tumor is most likely to stain positive for:

  1.        CEA
  2.        Adipophilin
  3.        S100
  4.        Ber-EP4

Sebaceous Carcinoma 4x Sebaceous Carcinoma 10x Sebaceous Carcinoma 10x 2 Sebaceous Carcinoma 20x

 Case history

71-year-old male veteran presenting with hematuria. Two ulcerated lesions identified upon gross examination. The diagnosis is:


  1.        Plasmacytoid variant of urothelial carcinoma
  2.        Plasmacytoma
  3.        Melanoma
  4.        Metastatic signet ring cell carcinoma

 Case history

A patient presents with extrahepatic cholangiocarcinoma, a biopsy of the liver shows the following:

Twitter case

What stain is most likely to be the most helpful to make the diagnosis?

  1.       Ki-67 
  2.       CK7
  3.       Arginase
  4.       No additional stains needed

thymoma 1 thymoma2 
thymoma3 thymoma4

Case history

An 84-year-old woman presents with a mediastinal mass.  Representative sections are shown.

What is the diagnosis?

  1.         Solitary fibrous tumor
  2.         Small lymphocytic lymphoma
  3.         Thymoma, Type A
  4.         Thymoma, Type AB

Twitter question MCI HE 10x Twitter question MCI HE 20x 

Case history

Placenta from a 33-year old P0 mother delivered at 25 6/7ths weeks. Maternal history of scleroderma. Fetal intrauterine growth restriction (<5th %ile).

Finding shown are characteristic of:

  1. Cytomegalovirus infection
  2. Chronic villitis of unknown etiology
  3. Massive perivillous fibrinoid deposition
  4. Chronic histiocytic intervillositis
  5. Listeria monocytogenes villitis

Fig A Fig B

Case history

A 76-year-old man with a history of HTN and CKD Stage III presented with increased serum Cr. Renal biopsy performed showed cellular and fibro-cellular crescents with fibrinoid necrosis by LM (Jones silver, Fig a & b). IF and EM were negative.

Which of the following information, based on LM findings, is helpful in making the diagnosis?

  1.     . Anti-dsDNA titer
  2.     . ANCA titer
  3.     . Anti-GBM antibodies.
  4.     . All of the above.

     Picture1 Picture2  
Picture3 Picture4

Case history

A 36 year old man presented to an OSH for an upper GI bleed. Biopsy was non diagnostic.  He was referred here for EUS-FNA.  US showed an 11 mm. hypoechoic submucosal mass in the lesser curvature (Fig 1).  EUS-FNA smear stained with Diff-Quik is moderately cellular (Fig 2-4). 


  1. Gastric adenocarcinoma
  2. Endocrine neoplasm
  3. Pancreatic heterotopia
  4. Epithelioid GIST

     Picture1 Picture2 

Case history

A pancreatic head mass was discovered in a 50-year-old man with chronic pancreatitis. Grossly, the lesion was ill-defined and notable for obstructing the main pancreatic duct while the common bile duct and ampulla were probe patent. The patient noted a mother who died of pancreatic cancer at 55 and that he’s been hospitalized for pancreatitis several times since his 20s. What is the underlying tumor and which of the following genes is not associated with hereditary pancreatitis?

  1. Pancreatic ductal adenocarcinoma, Mothers against decapentaplegic homolog 4 (SMAD4)
  2. Cholangiocarcinoma, Cystic fibrosis transmembrane conductance regulator (CFTR) mutations
  3. Acinar cell carcinoma, Serine protease inhibitor Kazal type 1 (SPINK1) mutations

     4x 10x SMAS 100

Case history:

This is a biopsy from the olfactory cleft (skull base) in a 71-year-old woman with rhinorrhea. Endoscopically there is a small nodule.

What is the diagnosis?

  1. Reactive stromal spindle cell proliferation
  2. Respiratory epithelial adenomatoid hamartoma
  3. Biphenotypic sinonasal sarcoma
  4. Solitary fibrous tumor