Ahmed Hussein

A histopathologist from Egypt.

[NotasDePatologia @Notas_Patologia]

🔬Prostatic stromal tumour of uncertain malignant potential – STUMP
(with emphasis on the differential diagnosis with prostatic stromal sarcoma)
A hypercellular prostatic stromal neoplasm with large, pleomorphic nuclei is necessarily a sarcoma? No. STUMP may show quite striking cytologic atypia — and recognizing its degenerative nature is one of the main diagnostic pitfalls. 🧵

🔬 Definition
STUMP is a rare mesenchymal neoplasm arising from the specialized prostatic stroma, characterized by uncertain biological behavior and absence of the unequivocal criteria of malignancy seen in prostatic stromal sarcoma (PSS).

📊 Epidemiology
• Rare.
• Occurs predominantly in adults.
• In general, patients are slightly older than those with PSS.

📍 Sites
• Prostate, involving the transition and/or peripheral zones.

🧬 Pathogenesis
• Unknown etiology.
• Genomic alterations are heterogeneous.
• STUMP and PSS may share some chromosomal alterations and coexist within the same prostate.
• However, there is no convincing demonstration of an obligatory STUMP → PSS sequence.

🩺 Clinical Features
• Lower urinary tract obstructive symptoms.
• Hematuria or hematospermia may occur.
• It may occasionally present as a prostatic mass.

🧪 Laboratory Diagnosis
• Serum PSA is not a specific marker of the neoplasm.
• Diagnosis is fundamentally histomorphologic.

🔬 Histopathology
Five patterns may be observed, either alone or in combination:

• Hypercellular stroma with atypical cells showing a degenerative appearance.
• Hypercellular spindle-cell stroma with cytologically bland features.
• Phyllodes/leaf-like pattern.
• Myxoid pattern.
• Epithelioid stromal pattern.
An important clue: very large, hyperchromatic, pleomorphic nuclei may be present, but isolated, without the overall constellation of changes expected in a sarcoma.

🧫 Immunohistochemistry
• Vimentin: positive.
• PR: frequently positive.
• CD34: variable.
• SMA/desmin: variable.
• ER: uncommon.
• KIT, S100, and STAT6: usually negative.

⚠️ None of these markers, in isolation, distinguishes STUMP from PSS. Morphology is central.

🔎 Differential Diagnosis
• Prostatic stromal sarcoma – favored by marked hypercellularity, non-degenerative pleomorphism, increased mitotic activity, atypical mitoses, and necrosis.
• Leiomyoma/leiomyosarcoma – convincing smooth muscle differentiation, with desmin/SMA/h-caldesmon.
• Solitary fibrous tumor – nuclear STAT6.
• GIST – DOG1 and KIT/CD117.
• Sarcomatoid carcinoma – look for epithelial differentiation and cytokeratin expression.

📈 Prognosis
Behavior is unpredictable, although most STUMPs do not show aggressive behavior. Local recurrence may occur, supporting the need for clinical follow-up.

💊 Treatment
There is no universal strategy due to the rarity of the disease. Localized lesions are usually treated surgically, considering size, extent, and the possibility of complete resection. Follow-up is recommended.

🎯 Take-Home Messages @Notas_Patologia
• Bizarre nucleus ≠ sarcoma: STUMP may show striking degenerative atypia.
• Look for the combination: mitoses + atypical mitoses + necrosis + non-degenerative pleomorphism to favor PSS.
• CD34 and PR may support specialized prostatic stromal differentiation, but do not resolve STUMP × PSS.
• In small samples, tumor heterogeneity is an important limitation.
• Morphology remains the key to diagnosis.

📚 Selected References
• WHO Classification of Tumours Editorial Board. Urinary and Male Genital Tumours. 5th ed. IARC.
• Bostwick DG, Egevad L. Prostatic stromal proliferations: a review. Pathology. 2021;53:12–25.
• Acosta AM et al. Re-evaluating tumors of purported specialized prostatic stromal origin. Mod Pathol. 2021;34:1763–1779.
• Gaudin PB et al. Sarcomas and related proliferative lesions of specialized prostatic stroma. Am J Surg Pathol. 1998;22:148–162.
• PathologyOutlines – Prostatic stromal tumors: https://t.co/yteSms2T6w

⚠️Disclaimer⚠️
This text is an educational summary for healthcare professionals and students. It does not replace full pathology reports, local guidelines, or individualized clinical decision-making.
#MedicalEducation #NotasDePatologia #Pathology #PathTwitter #GUPath #Uropathology

[Kathryn Lindsey @PathologyKate]

What is the clinical history? #BoardFodder

[Patrick’s Rare Books @patricksrarebks]

Follow the oxygen.

[allen institute @AllenInstitute]

Holy Soma Batman!

You never know what you may find when you cruise our MICrONS Explorer, such as a blood vessel piercing the soma of a neuron!

👀 See this incredible find up close using this shortcut: https://t.co/QkoavsnhtS

[Charlie Herndon @DrCycloPath]

✅ Gastric-type Adenocarcinoma 🎯🧬
• Aggressive HPV-independent adenocarcinoma exhibiting gastric (pyloric) differentiation.
• Glands show voluminous clear or pale eosinophilic cytoplasm, distinct cell borders, and neutral mucins.
• Frequently associated with STK11 mutations and Peutz-Jeghers syndrome, with abnormal p53 expression.
• Importantly, p16 is typically negative or patchy, distinguishing it from HPV-associated tumors.

[Charlie Herndon @DrCycloPath]

#PathQuiz 🔬🧬 #GynPath

A) HPV-associated Adenocarcinoma
B) Clear Cell Adenocarcinoma
C) Lobular Endocervical Glandular Hyperplasia
D) Gastric-type Adenocarcinoma

#Pathology #GynPath

[Science Magazine @ScienceMagazine]

When cells grow together, they often align with their neighbors, forming liquid crystal-like patterns known as “nematic order.” But that order isn’t perfect, and at certain points, the alignment can break down, creating “topological defects”: small regions where cells swirl or fan out instead of lining up cleanly.

And according to research published in Science, what looks like a defect can be used strategically as built-in instructions for shaping larger structures. Instead of growing upward, cells can store and release stress in certain places along a previously flat sheetlike structure, forming a bowl, a ridge, or a fold.

Learn more: https://t.co/OSMGhNzR6d

[Ahmed Hussein @Pathologist_001]

@AMontasserMD جميل قوي! تسلم ايدك ربنا يبارك عليك 🤍

[Ahmed Montasser @AMontasserMD]

@TungPath In my example, my first clue was they were a bit more abundant than a needle carry over, then the brush border-like condensations: normal gatric foveolar mucosa doesn’t have that.

[Ahmed Hussein @Pathologist_001]

@drkeithsiau A histopathologist can go mad when he received the gallbladder open 😺

[Syed Z. Ali @sza_jhcyto]

"In cytopathology, one signet ring cell may whisper, but a cluster always shouts malignancy." Hepatic hilar node with metastatic colonic adenocarcinoma, signet ring cell type. (FNA, Smear and Cell block).

[Ateeqa Mujeeb Ullah @UllahAteeqa]

📣Excited to share our recent article on the practical approach to gastric lesions; the background mucosa & new nomenclatures!

Deeply grateful to Dr. Elizabeth Montgomery for her incredible support, mentorship & guidance.

https://t.co/tXBJEMzcLl

@LizMontgomeryMD #PathX #GIPath

[Benard Solomon @BenServiceNotes]

ABC Of Cytology_30
2026
Carcinoid tumour
Carcinoid tumors are low-grade neuroendocrine neoplasms, most often associated with the lung or gastrointestinal tract (GIT). In cytology FNA/ EBUS-FNA, or bronchial brushings, they are observed as a uniform population

[J.K. Rowling @jk_rowling]

Nearly thirty years as a published writer and this is the first time I’ve used a new device that became instantly irreplaceable (no, I’m not being paid to say this.) It feels like using ink and paper and does everything I want it to do and nothing I don’t need it to do.

I know I’m late to the party, but my son gave it to me on my birthday so to me it’s a very recent revelation. It’s already joined my laptop at the top of my Things I Dread Losing list. #supernote

[Janira Navarro @Janiranavarro]

HTT (hyalinizing trabecular tumor)

Rare follicular-derived thyroid tumor with trabecular growth, hyalinized stroma, and PTC-like nuclei

Once considered a PTC variant; now regarded as benign or of low malignant potential.

Shows unusual membranous/cytoplasmic MIB-1 (Ki-67) staining, but only when the stain is done at room temperature (rarely seen in routine practice)

Dr. Scognamiglio #USCAP #pathology #PathX #PathTwitter

[Elizabeth Montgomery, MD @LizMontgomeryMD]

Another classic "KIT"fall - metastatic melanoma presenting as a gastric polyp. Melanomas often express KIT/CD117.

[C.Alberto Ortega @albertoortegana]

Which hand lesion is classically associated with DIP osteoarthritis and longitudinal nail grooving?
A. Glomus tumor
B. Digital myxoid (mucous) cyst
C. Pyogenic granuloma
D. Herpetic whitlow

[Histopathology @Histo_Journal]

The 6th edition of the WHO classification of tumours of the breast (2026) is now in use. Here is a comprehensive, well-illustrated, practical summary by a group of leading experts of the main changes since the last edition. #openaccess #breastpathology
https://t.co/pMWu3oIxm6

[Keith Siau @drkeithsiau]

According to @grok, the green stuff on this lobster is the hepatopancreas, hence the bile-like colour. Chefs and food connoisseurs call this tomalley. Now that you know, would you still eat it?

[Stanford Medicine @StanfordMed]

What can pythons teach us about fat and metabolism? A Stanford Medicine researcher studies the dramatic metabolic shifts pythons undergo after eating — and what they could reveal about appetite, metabolism and weight loss in humans. https://t.co/p1UkXoXWTB
@StanfordBrain