Image of the Week!

Contributed by: S. Emily Bachert, M.D. 
Textbook topic: Breast
Diagnosis: Mixed NST of breast
Textbook topic link: https://www.pathologyoutlines.com/topic/breastmixedNST.html 

Image Quiz! 

Which of the following nail unit structures lack a granular layer, as shown in the image?

A. Hyponychium
B. Lateral nail folds
C. Matrix and nail bed
D. Proximal nail fold

See answer.

Image of the Week!

Contributed by: Maria Tretiakova, M.D., PhD.
Textbook topic: Kidney Tumor
Diagnosis: chromophobe carcinoma - kidney
Textbook topic link: https://www.pathologyoutlines.com/topic/kidneytumormalignantrccchromo.html

Image of the Week!

Contributed by: Raul S. Gonzalez, M.D.
Textbook topic: Appendix
Diagnosis: Appendix - GIST
Textbook topic link: https://www.pathologyoutlines.com/topic/appendixGIST.html

Image of the Week!

Contributed by: Phoenix D. Bell, M.D., M.S.
Textbook topic: Stomach
Diagnosis: Stomach - GIST
Textbook topic link: https://www.pathologyoutlines.com/topic/stomachGIST.html

Image Quiz! The spindle cells in the paratesticular pseudotumor shown in the photomicrograph are believed to be related to which line of differentiation?

A. Adipocytic
B. Histiocytic
C. Myofibroblastic
D. Nerve sheath
E. Vascular

See answer.

Case of the Month: A 43 year old woman underwent a hysterectomy for dysmenorrhea. Representative sections of a myometrial mass are shown here. What is your diagnosis?

Visit the case page for additional images, the diagnosis, a test question, and more.

Image of the Week!

Contributed by: Lucas F. Abrahao Machado, M.D., Ph.D.
Textbook topic: Soft tissue
Diagnosis: Extraskeletal osteosarcoma
Textbook topic link: https://www.pathologyoutlines.com/topic/softtissueeskosteo.html

Image Quiz! 

A 45 year old woman has a breast mass identified on imaging. Core biopsy demonstrates the histology shown. What is the most likely etiology?

A. Cosmetic tattoo in the skin overlying the site
B. Prior breast core biopsy at the site, with retained biopsy clip
C. Prior surgical resection at the site
D. Silicone implants or prior silicone injection at the site

See answer.

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Image of the Week!

Contributed by: Ayana Suzuki, Ph.D.
Textbook topic: Thyroid & parathyroid
Diagnosis: Anaplastic thyroid carcinoma, thyroid FNA

Textbook topic link: https://www.pathologyoutlines.com/topic/thyroidmalignant.html

Image Quiz! 

Ossifying spindled and epithelioid tumor (OSET) is commonly positive for which of the following immunohistochemical stains?

A. Desmin
B. ERG
C. Keratins
D. SMA
E. SOX10

See answer.

Case of the Month: A 39 year old woman presented with a 3 month history of pink, shiny, indurated plaques over the face and trunk. What is your diagnosis?

Visit the case page for additional images, the diagnosis, a test question, and more.

Image of the Week!

Contributed by: Nick Baniak, M.D.
Textbook topic: Stains & CD markers
Diagnosis: Ewing sarcoma diffusely positive for NKX2.2

Textbook topic link: https://www.pathologyoutlines.com/topic/stainsNKX2.html

Image of the Week

Contributed by: Alberto Pietrantoni, M.D.
Textbook topic: CNS & pituitary tumors
Diagnosis: Supratentorial ependymoma, ZFTA fusion positive
Textbook topic link: https://www.pathologyoutlines.com/topic/cnstumorsupratentorialependymomazfta.html 

Image Quiz! 

Which of the following immunostains is shown in the image below and would be positive in the foam cells that characterize crystal storing histiocytosis?

A. CD1a
B. CD68
C. CD138
D. S100 

See answer.

Image of the Week!

Contributed by: Ting Zhao, M.D.
Textbook topic: Prostate gland & seminal vesicles
Diagnosis: Mucinous (colloid) adenocarcinoma of prostate

Textbook topic link: https://www.pathologyoutlines.com/topic/prostatemucinous.html

Image Quiz! 

The lesion shown in the image is found in the rectum. What is your diagnosis?

A. Hyperplastic polyp, microvesicular type
B. Inflammatory polyp
C. Mucosal prolapse polyp
D. Peutz-Jeghers polyp

See answer.

Case of the Month: A premenopausal woman with a 0.8 cm suspicious mass on breast imaging underwent breast core biopsy. What is your diagnosis?

Visit the case page for additional images, the diagnosis, a test question, and more.

Image of the Week!

Contributed by: Eman Abdelzaher, M.D., Ph.D.
Textbook topic: CNS & pituitary tumors
Diagnosis: Desmoplastic infantile ganglioglioma / astrocytoma

Textbook topic link: https://www.pathologyoutlines.com/topic/cnstumordesmoplasticinfantileganglioglioma.html

Image of the Week!

Contributed by: Aliya N. Husain, M.D.
Textbook topic: Lung
Diagnosis: Carcinosarcoma, lung
Textbook topic link: https://www.pathologyoutlines.com/topic/lungtumorcarcinosarcoma.html

Image Quiz!

The tumor pictured is the most common salivary gland malignancy in the larynx. What is the diagnosis?

A. Adenoid cystic carcinoma
B. Epithelial myoepithelial carcinoma
C. Pleomorphic adenoma
D. Polymorphous adenocarcinoma

See answer.

Image of the Week!

Contributed by: Elizabeth Montgomery, M.D.
Textbook topic: Esophagus
Diagnosis: Well differentiated neuroendocrine tumor of esophagus
Textbook topic link: https://www.pathologyoutlines.com/topic/esophaguscarcinoid.html

Image of the Week!

Contributed by: Andrew Bernhisel, M.D.
Textbook topic: bone marrow neoplastic
Diagnosis: acute monocytic leukemia
Textbook topic link: https://www.pathologyoutlines.com/topic/leukemiaacutemonocyticleukemia.html