Short power list

The short power list is a short differential diagnosis for the most common specimens. This list is written for junior residents and should serve as a starting point if one has no clue about the differential diagnosis for the site. It assumes the specimen comes from an adult. There is an expanded long power list.

Bone

General

Benign:

• Aneurysmal bone cyst.
• Osteoid osteoma.

Malignant:

• Metastatic carcinoma.
• Plasma cell neoplasm.
• Osteosarcoma.
• Ewing sarcoma.

Femoral head

Benign:

• Osteoarthritis.
• Avascular necrosis of the femoral head.
• Rheumatoid arthritis.

Uncommon - benign (fracture):

• Trauma.
• Osteoporosis.

Uncommon - benign pediatric:

• Slipped capital femoral epiphysis (SCFE).
• Legg–Calvé–Perthes syndrome.

Uncommon - malignant (fracture):

• Metastasis.

Breast pathology

Benign:

• Normal.
  • Lactational change.
• Fibrocystic change.
• Fibroadenoma.
• Columnar cell change.
• Sclerosing adenosis.

Malignant:

• DCIS.
• LCIS.
• Ductal carcinoma.
• Invasive lobular carcinoma.
• Tubular carcinoma of the breast.

Uncommon benign/malignant:

• Phyllodes tumour.

Cardiovascular pathology

General

• Thrombosis (embolism).
• Vasculitis.

Uncommon:

• Amyloid deposition.
• Hyperplastic arteriolosclerosis.

Aorta

• Atherosclerosis.

Uncommmon:

• Cystic medial degeneration.

Aortic valve

• Calcific aortic stenosis.

Uncommon:

• Infective endocarditis.
• Myxomatous degeneration.
• Papillary fibroelastoma.

Mitral valve

• Rheumatic heart disease.

Uncommon:

• Myxomatous degeneration.
• Infective endocarditis.

Heart

• Myocardial infarction.
• Atrial myxoma.

Uncommon - benign:

• Lipoma.
• Rhabdomyoma.

Uncommon - malignant:

• Pleomorphic undifferentiated sarcoma.
• Angiosarcoma.

Dermatopathology

Benign - non-melanocytic:

• Epidermal inclusion cyst.
• Lipoma.
• Dermatofibroma.
• Dermal scar.

Benign melanocytic lesions:

• Intradermal nevus.
• Junctional nevus.
• Congenital nevus.
• Clark nevus.
• Spitz nevus.

Malignant:

• BCC.
• SCC.
• Malignant melanoma.
• DFSP.

Endocrine pathology

Thyroid gland

Benign:

• Thyroid gland nodular hyperplasia.
• Lymphocytic thyroiditis.
• Noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP).

Malignant:

• Papillary thyroid carcinoma (NOS).
• Papillary thyroid carcinoma follicular variant.

Uncommon - malignant:

• Papillary thyroid carcinoma columnar cell variant.
• Papillary thyroid carcinoma tall cell variant.
• Medullary thyroid carcinoma.
• Anaplastic thyroid carcinoma.

Adrenal gland

Benign:

• Adrenal cortical adenoma.

Malignant:

• Adrenal cortical carcinoma.
• Pheochromocytoma.

Gastrointestinal pathology

Gastrointestinal polyp

Benign:

• Normal.
• Hyperplastic polyp.
• Inflammatory pseudopolyp (inflammatory bowel disease).

Pre-malignant:

• Tubular adenoma.
• Villous adenoma.
• Tubulovillous adenoma.
• Sessile serrated adenoma.

Uncommon - pre-malignant:

• Traditional serrated adenoma.

Esophagus

Benign:

• Gastroesophageal reflux disease.
• Eosinophilic esophagitis.
• Barrett esophagus.

Benign - uncommon:

• Herpes esophagitis.

Malignant:

• Squamous cell carcinoma.
• Adenocarcinoma.

Stomach

Benign:

• Helicobacter pylori gastritis.
• Intestinal metaplasia.
• Chronic gastritis.
• Acute gastritis.

Pre-malignant:

• Gastric dysplasia.

Malignant:

• Adenocarcinoma, intestinal type.
• Signet-ring cell carcinoma.
• GIST.
• MALT lymphoma.

Duodenum

Benign:

• Normal.
• Celiac disease.

Pre-malignant:

• Tubular adenoma.

Malignant:

• Adenocarcinoma.

Uncommon benign:

• Giardiasis.
• Whipple disease.
• MAI infection.

Colon/rectum

Benign:

• Normal.
• Colitis. e.g. IBD.
• Hyperplastic polyp.
• Tubular adenoma.
• Tubulovillous adenoma.
• Villous adenoma.
• Sessile serrated adenoma.

Benign - uncommon infectious:

• Pseudomembranous colitis.

Benign - uncommon:

• Lymphocytic colitis.
• Collagenous colitis.
• Inflammatory polyp.
• Juvenile polyp.
• Peutz-Jeghers polyp.

Tumour:

• Gastrointestinal stromal tumour.
• Schwannoma.
• Neuroendocrine tumour.

Malignant:

• Colorectal adenocarcinoma.

Appendix

Benign:

• Appendicitis.
• Periappendicitis.
• Crohn's disease.
• Normal.

Neoplasm:

• Neuroendocrine tumour.
• Low-grade appendiceal mucinous neoplasm (LAMN).

Malignant:

• Mucinous adenocarcinoma.

Liver

Benign:

• Steatosis.
• Steatohepatitis.
• Hepatitis B.
• Hepatitis C.

Malignant:

• Metastatic adenocarcinoma.
• Hepatocellular carcinoma.

Uncommon benign:

• Autoimmune hepatitis.
• Primary sclerosing cholangitis, esp. in the context of UC.
• Primary biliary cholangitis.
• Wilson's disease.
• Hereditary hemochromatosis.
• Alpha-1 antitrypsin deficiency.

Uncommon malignant:

• Cholangiocarcinoma.

Gallbladder

Benign:

• Cholelithiasis.
• Cholesterolosis.
• Acute cholecystitis.
• Chronic cholecystitis.

Uncommon - risk for dysplasia:

• Intestinal metaplasia.

Uncommon - malignant:

• Adenocarcinoma.

Genitourinary pathology

Tumour kidney

Benign:

• Normal kidney.
• Renal oncocytoma.
• Angiomyolipoma.
• Renal papillary adenoma.

Malignant:

• Clear cell renal cell carcinoma.
• Papillary renal cell carcinoma.
• Chromophobe renal cell carcinoma.
• Urothelial carcinoma.

Uncommon - benign:

• Xanthogranulomatous pyelonephritis.

Medical kidney

• Diabetic nephropathy.
• Systemic lupus erythematosus.

Prostate gland

Benign:

• Normal.
• Chronic inflammation.
• Acute inflammation.
• Benign prostatic hyperplasia (prostatectomy diagnosis only).

Pre-malignant:

• High grade prostatic intraepithelial neoplasia.

Malignant:

• Acinar adenocarcinoma.

Uncommon - malignant:

• Ductal adenocarcinoma.
• Urothelial carcinoma.
• Foamy gland carcinoma - mimics benign prostate.
• Pseudohyperplastic adenocarcinoma - mimics benign prostate.
• PIN-like prostatic ductal adenocarcinoma - mimics HGPIN.

Urinary bladder

Benign:

• Inverted urothelial papilloma.
• Cystitis cystica.

Pre-malignant/malignant:

• Urothelial dysplasia.
• Low grade papillary urothelial carcinoma.
• High grade papillary urothelial carcinoma.
• Flat urothelial carcinoma.

Uncommon - benign:

• Malakoplakia.
• Nephrogenic adenoma.

Testis

• Germ cell neoplasia in situ (intratubular germ cell neoplasia).
• Seminoma.
• Embryonal carcinoma.
• Yolk sac tumour.
• Teratoma.
• Mixed germ cell tumour.
• Leydig cell tumour.
• Sertoli cell tumour.

Gynecologic pathology

Uterus

Benign:

• Fibroids.
• Adenomyosis.
• Atrophy.
• Uterine prolapse.
• Proliferative phase endometrium.
• Secretory phase endometrium.

Pre-malignant:

• Complex endometrial hyperplasia.

Malignant:

• Endometrial carcinoma.
  • Endometrioid.
  • Mucinous.
  • Serous.

Uncommon - benign:

• Decidua (change of pregnancy).

Uncommon - malignant:

• Clear cell carcinoma.
• Carcinosarcoma.

Cervix - cytology

Benign:

• Normal.
• Candida.
• Endometrial cells.
• Atrophy.

Pre-malignant/malignant:

• LSIL.
• HSIL.
• Squamous cell carcinoma.
• Adenocarcinoma.

Uncommon - benign:

• HSV changes.
• Trichomonas.

Ovary

Benign:

• Serous cystadenoma.
• Mucinous cystadenoma.
• Mature teratoma.
• Endometriosis.

Malignant:

• Serous carcinoma.
• Endometrioid carcinoma.
• Mucinous carcinoma.

Uncommon - malignant:

• Dysgerminoma.

Fallopian tube

Benign:

• Paratubal cyst.
• Tubo-ovarian abscess.
• Salpingitis.
• Ectopic pregnancy.
• Adenomatoid tumour.

Pre-malignant:

• Serous tubal intraepithelial carcinoma (STIC).

Malignant:

• Serous carcinoma.

Uncommon - benign:

• Salpingitis isthmica nodosa.

Head and neck

General

Benign:

• Sinonasal papilloma.
• Vocal cord nodule.

Malignant:

• Squamous cell carcinoma of the head and neck.
• Nasopharyngeal carcinoma.
• HPV-associated squamous cell carcinoma of the head and neck.

Uncommon - malignant:

• Paraganglioma (carotid body tumour).

Salivary gland

Benign:

• Pleomorphic adenoma.
• Warthin tumour.

Malignant:

• Mucoepidermoid carcinoma.
• Adenoid cystic carcinoma.

Uncommon benign:

• Benign lymphoepithelial cyst.
• Basal cell adenoma.
• Canalicular adenoma.
• Oncocytoma.

Uncommon malignant:

• Acinic cell carcinoma.
• Polymorphous adenocarcinoma - previously known as polymorphous low-grade adenocarcinoma.
• Carcinoma ex pleomorphic adenoma.
• Salivary duct carcinoma.
• Hyalinizing clear cell carcinoma.

Lymph node

Benign:

• Normal/resting.
• Follicular hyperplasia.
• Lymph node hyalinization.

Malignant:

• Lymph node metastasis, esp. carcinoma.
• Chronic lymphocytic leukemia.
• Follicular lymphoma.
• Diffuse large B cell lymphoma.
• Nodular sclerosis Hodgkin lymphoma.
• Mixed cellularity Hodgkin lymphoma.
• MALT lymphoma.

Pulmonary pathology

Benign:

• Normal.

Malignant:

• Adenocarcinoma.
• Squamous carcinoma.
• Small cell carcinoma.

Uncommon - benign:

• Tuberculosis.
• Sarcoidosis.
• Usual interstitial pneumonia.
• Solitary fibrous tumour - esp. pleural.

Uncommon - malignant:

• Mesothelioma.

Soft tissue

Benign:

• Lipoma.
• Hemangioma.
• Neurofibroma.

Malignant:

• Liposarcoma.
• Pleomorphic undifferentiated sarcoma.
• Chondrosarcoma.

Spleen

Benign:

• Trauma.
  • Splenic laceration.
• Normal.
• Enlargement due to cirrhosis.

Malignant:

• Diffuse large B cell lymphoma.
• Splenic marginal zone lymphoma.
• Follicular lymphoma.
• Hairy cell leukemia.

Placenta

• Normal.
• Chorioamnionitis.
  • Funisitis.
• Meconium.
• Placentomegaly.
• Placental infarction.

Less common:

• TORCH infections.
• Chorangioma.
• Chorangiosis.
• Villitis of unknown etiology.

Brain

• Normal
• Reactive changes.
• Multiple sclerosis.
• Encephalitis.
• Neurodegeneration.
• Neoplastic.

See also

• Diagnosis.
• Long power list.