Cancer of unknown primary

Question 1

CK7+/CK20+

Answer 1

• Extrahepatic carcinoma of the bile duct
• Gastric adenocarcinoma, subset (majority are CK7+ / CK20-) (see below)
• Pancreatic adenocarcinoma, minor subset (co-expression associated with worse prognosis, however, majority are CK7+ / CK20-) (see below)
• Primary mucinous tumors of the ovary (74%)
• Pulmonary invasive mucinous adenocarcinoma subset (17%)
• Small intestinal adenocarcinoma (67%)
• Urothelial carcinoma (60%)

Question 2

CK7+/CK20-

Answer 2

• Breast carcinoma
• Cervical squamous cell carcinoma and adenocarcinoma
• Endometrial adenocarcinoma
• Esophageal adenocarcinoma
• Gastric adenocarcinoma (71% CK7+, 30% CK20+)
• Lung acinar adenocarcinoma
• Mesothelioma (pleural and peritoneal)
• Ovarian adenocarcinoma, including endometrioid, clear cell, serous, seromucinous
• Pancreatic adenocarcinoma (majority but see also above)
• Renal cell carcinoma, papillary, chromophobe and clear cell papillary types
• Thyroid tumors (adenoma and carcinoma) (Appl Immunohistochem Mol Morphol 2000;8:189)
• Urothelial carcinoma (30%)

Question 3

TTF1 (thyroid transcription factor) stains positive in which malignancies?

Answer 3

• lung adeno
• medullary thyroid cancer

Question 4

sarcoma stains to know

Answer 4

Vimentin and desmin are specific for?

Question 5

melanoma stains to know

Answer 5

HMB45
S100

Question 6

CK7-/CK20+

Answer 6

• Colorectal carcinoma
• Merkel cell carcinoma

Question 7

CK7-/CK20-

Answer 7

• Adrenal cortical carcinoma and adenoma
• Germ cell tumor, seminoma and embryonal carcinoma subtypes
• Hepatocellular carcinoma
• Pituitary adenoma
• Prostatic adenocarcinoma
• Renal cell carcinoma, clear cell type
• Squamous cell carcinoma

Question 8

Cytogenetic finding specific for germ cell tumors

Answer 8

isochrome 12p

Question 9

Empiric chemotherapy for cancer of unknown primary

Answer 9

carbo taxol

Question 10

Management of female with peritoneal carcinomatosis + adeno of unknown prmary

Answer 10

• consider as ovarian primary and do surgical cytoreduction w/ adjuvant platinum based chemotherapy

Question 11

Management of upper cervical lad + squamous cell of unknown primary

Answer 11

• scope pyriform sinuses, nasopharynx, base of tongue, bilateral tonsils
• check p16 (positive indicates)

Question 12

Management of inguinal LAD in setting of CUP

Answer 12

• treat as anal or genital primary

Question 13

Management of isolated bone met in setting of CUP

Answer 13

• prostate primary in men, breast in women