Seminoma

• #1 testicular germ cell tumor
• Syncytiotrophoblastic cells may be seen
• Associated testicular atrophy can be seen 👇
• IHC:
OCT3/4; KIT/CD117; SALL4 +
CD30 and AFP -

#pathagonia #pathx #gupath #pathology #seminoma #pathology #medx

Mucocele-like Lesion (Breast)

• Dilated cysts+ducts w mucin
• Often rupture with mucin extravasation into stroma
• Calcifications common
• Look at epithelium to rule out ADH, DCIS
• If tumor cells floating inside mucin, think mucinous carcinoma

Photo credit:Kelly Hall, MD

S100

• Stains Schwann cells and melanocytes
• Stains Adipocytes
• Stains (I often forget) myoepithelial cells in breast too 👇

#pathagonia #path4people #pathx #ihc #s100 #pathtwitter #breastpath

Gastric Xanthoma

• Benign
• Endoscopically 👀 as yellow-white nodules
• Most common location-Antrum
• Foamy macrophages in lamina propria
• Etiology unclear
• Associated with background gastric pathology

#pathagonia #path4people #gi path #pathx #gi #gastroenterology

Spironolactone Bodies

• Concentric lamellations 👇
• Seen in adrenal tissue of pts with primary hyperaldosteronism (Conn syndrome) treated with aldosterone anatogonists (eg. Spironolactone)
• Adrenalectomy done as medications were ineffective

#pathagonia #pathx #pathtwitter

Complex Fibroadenoma

Needs one or more:

1) Cysts greater than 3 mm
2) Epithelial (not stromal) calcifications (see below)
3) Papillary apocrine Metaplasia
4) Sclerosing adenosis

⬆️ relative risk ~ 3x for breast cancer (citation 👇)

#pathagonia #path4people #pathx #breastpath

Intravenous (Lipo)Leiomyomatosis

• A mouthful but basically a fibroid w fat elements inside a vessel that itself is outside a fibroid
• Not staged
• Extrauterine extension occurs ~ 30% of times
• This case also had a broad ligament leiomyoma

#pathagonia #gynpath

Fibroadenoma

• Fibroepithelial lesion with median age of 25 years old.

• Benign but 1.5-2x increased relative risk of breast cancer

• For fibroadenomas, rule out any involved atypia

👇 LCIS involving Fibroadenoma

Image credit: Michelle Josey, MD
#pathagonia #pathx

Great learning point tying in Ovary tumors with Endocrine Hormonal Symptoms

Oluwole Fadare, MD presenting @ San Antonio Society of Pathologists

👇 #pathx #pathagonia #pathtwitter #surgpath #gynpath #obgyn #gynonc

Hashimoto Thyroiditis

• #1 cause of hypothyroidism in iodine sufficient regions
• 🔬 lymphoplasmacytic infiltration, follicles w germinal centers, oncocytes, fibrosis
• Increased risk of primary thyroid lymphoma and papillary thyroid carcinoma

#pathagonia #pathx #medstudent

HSIL

• Nucleoli can be tricky because it can be seen in reactive conditions.

• But sometimes they can be seen in HSIL esp when it involves endocervical glands

#pathagonia #pathx #path4people #gynpath #obgyn #hpv #hsil #pathtwitter #pathology #gynx #obgyn x #surgpath #medx

Embryonal Carcinoma

• #2 most prevalent testicular germ cell tumor (after seminoma)

• Peak incidence is 30 y/o (10 years younger than seminoma)

• Most common element seen in mixed germ cell tumor.

• IHC: CD30 and AE1/AE3 +

Image Credit: Kelly Hall, MD

#pathagonia

Neuroendocrine Tumor (NET) of Appendix

• 80% are found incidentally after surgery for appendicitis
• Most common location: tip
• Not always nested architecture: can be trabeculated, in acini,and ribbons

Pretty subtle in my opinion👇

#pathagonia #path4people #pathx #medx

Solitary fibrous tumor (SFT)

• Fibroblastic tumor; can occur anywhere in body
(superficial +deep soft tissue, bone, visceral organs, CNS, salivary gland)

• Peak incidence:40-70 y/o; may undergo mets

• Molecular: NAB2-STAT6 fusion

Image credit: Kelly Hall, MD
#pathagonia

Oncocytoma of Kidney

• Benign
• ~ 6-9% of kidney tumors
• average age: 62 y/o
• grossly: can be mahogany brown with central stellate scar
• If hybrid features of chromophobe, think Birt-Hogg-Dube syndrome (mutation in FLCN)

Slide credit: Evan Tweed, MD
#pathagonia #pathx

Schwannoma

• Benign tumor derived from Schwann cells (CNS WHO G1)

• There can be scattered atypical nuclei (ancient change)👇

• Look for Antoni A (in which there are Verocay bodies) and Antoni B

• If bilateral vestibular schwannoma, think NF2 (Merlin)

#pathagonia #pathx

Malignant Phyllodes Tumor

•More frequent among Hispanics in Central+South America

•Malignant heterologous diff will get you to malignant phyllodes (exception: well-diff liposarcoma)

• Ddx: primary or metastatic sarcoma +metaplastic carcinoma (would be cytokeratin+)

4 Molecularly Defined Endometrial Cancer:

• POLE ultramutated (best prognosis)
• Microsatellite Instability
• Copy number low
• Copy number high

Article below 👇

#pathagonia #pathx #surgpath #gyn path #gyn

Neurofibroma

•Benign nerve sheath tumor
•Neoplastic cell is schwann cell (other associated cells- perineurial and stromal cells)
•Subtypes: ancient, cellular, atypical, plexiform👇
•Plexiform is multinodular, look like “bag of worms”, ass w NF1+risk of MPNST transformation