Toby Schmitt, MD

Dermpath fellow | Developer of

[Toby Schmitt, MD @TobyASchmitt]

Couldn't be more excited to announce the launch of https://t.co/iJqFUSnnfj, the virtual slide site I wish had existed during my pathology residency. You can:
- Order special stains to work up cases
- See annotated histologic features
- Prepare for exams with board-style questions

[Toby Schmitt, MD @TobyASchmitt]

@ReyPathology Are you referring to the whole slide image (on the left) or the static images from the differential diagnoses (on the right)?

[Toby Schmitt, MD @TobyASchmitt]

New https://t.co/iJqFUSnnfj cases dropped: We're past the 1450 cases mark. Try your hand at working up this challenging soft tissue tumor (case #1450).

(Hint: FOSB IHC+)

[Toby Schmitt, MD @TobyASchmitt]

@tanimomotunde @LFpath Epithelioid angiosarcoma's in the differential, but it wouldn't be positive for FOSB

[Toby Schmitt, MD @TobyASchmitt]

Acute vacuolar interface change with dyskeratosis: A pattern with a narrow differential:
* Erythema multiforme, TEN/SJS
* Fixed drug eruption (usually has dermal melanin)
* Acute GvHD
* Reactive infectious mucocutaneous eruption (RIME)

WSI & discussion:
https://t.co/25HMLFWZxu

[Toby Schmitt, MD @TobyASchmitt]

Chronic colitis with pyloric gland metaplasia (top left) and Paneth cell metaplasia (bottom right - their granules look similar to eosinophil cytoplasm). Paneth cells are normal in the right side of the colon but signify colitis in the left side.

WSI: https://t.co/wFMGJPe9MQ

[Toby Schmitt, MD @TobyASchmitt]

A case of Ewing sarcoma metastatic to the skin with a classic "light cell/dark cell" appearance.

See the labelled whole slide at: https://t.co/HH8gzLzKEN

[Toby Schmitt, MD @TobyASchmitt]

A case of pityriasis lichenoides showing its classic features: Mounds of parakeratosis, red cell extravasation, lichenoid inflammation, and lymphocytic exocytosis.

Labelled whole slide: https://t.co/eKBkyHOaUu

[Toby Schmitt, MD @TobyASchmitt]

A bizarre parosteal osteochondromatous proliferation (BPOP) with disorganized cartilage, disorganized bone, and bland fibrous tissue.

BPOP is benign but locally destructive and has a propensity for the small bones of the hands & feet.

Labelled WSI: https://t.co/2QQi5QBsSO

[Toby Schmitt, MD @TobyASchmitt]

@BaiBai31141 This would be a tough one to get on frozen, although the monomorphic cytology would point away from clear cell carcinoma.

[Toby Schmitt, MD @TobyASchmitt]

A case of a Wolffian tumor (previously female adnexal tumor of probable Wolffian origin/FATWO).

These lesions typically show a variety of architectural patterns including tubular, cystic, and solid. Tubules filled with eosinophilic material are common.

WSI: https://t.co/3h7Q3zH7YS

[Toby Schmitt, MD @TobyASchmitt]

Atypical endometrial hyperplasia (top) and background benign endometrial glands (bottom). Note the contrast between small, dark benign nuclei and enlarged, pale, vesicular nuclei of atypical hyperplasia.

Labelled whole slide: https://t.co/fJHxxj30so

[Toby Schmitt, MD @TobyASchmitt]

A desmoplastic nodular medulloblastoma showing characteristic paler areas among more densely-packed small round blue cells.

Molecularly, this subtype of medulloblastoma tends to be SHH (sonic hedgehod pathway)-activated.

See the whole slide at:
https://t.co/nqQuJjhU7A

[Toby Schmitt, MD @TobyASchmitt]

Hyalinizing trabecular tumor is an aptly-named benign thyroid neoplasm. Ki-67 shows an unusual membranous pattern in these lesions.

What other lesion characteristically shows this Ki-67 staining pattern? Answer at: https://t.co/X5GEc7BBuq

[Toby Schmitt, MD @TobyASchmitt]

Trying to combat the number of bot accounts signing up for PathLibrary...

[Toby Schmitt, MD @TobyASchmitt]

A verrucous cyst showing the same papillomatosis, hypergranulosis, and coarse keratohyalin granules of verruca vulgaris.

These lesions may result from low-risk HPV infection of pre-existing epidermoid cysts.

Whole slide:
https://t.co/YwCBGMxYob

[Toby Schmitt, MD @TobyASchmitt]

Plexiform fibrohistiocytic tumors are rare soft tissue tumors of intermediate malignant potential.

They have a plexiform (woven) architecture with fascicles of histiocytoid cells in a collagenous stroma.

See the whole slide:
https://t.co/tHFaunZMjD

[Toby Schmitt, MD @TobyASchmitt]

A case of calcifying fibrous tumor, an entity characterized by dense, compact collagen and scattered calcification. These lesions may represent burnt-out IgG4-related disease.

Whole slide:
https://t.co/ofnMqaNVhH

[Toby Schmitt, MD @TobyASchmitt]

A case of hyaline vascular Castleman disease showing atretic (miniaturized) germinal centers with transgressing hyalinzed vessels as well as germinal center "twinning" (two germinal centers surrounded by a single mantle zone).

Labelled WSI: https://t.co/IclG2XoK0P

[Toby Schmitt, MD @TobyASchmitt]

@HENRYY_MD @et565 @david_terrano @melanopath @redsnapperpath @Dermpathl @gonzadetoro @SGottesmanMD Tricky but I favor verruca vulgaris with "actinic change"

[Toby Schmitt, MD @TobyASchmitt]

A case of acantholytic squamous cell carcinoma in situ.

Acantholysis in squamous cell carcinoma was once thought to confer a worse prognosis, but this is no longer thought to be the case.

Whole slide:
https://t.co/tqxyR82YlD