The Histopathologoid

1. Irregular infiltration of glands associated with altered fibroblastic stroma (desmoplastic response), OR 2. Confluent glandular pattern (cribriform), OR 3. Extensive papillary pattern, OR 4. Severe cytologic atypia (grade 3)

Microabscess in placenta: Differentials include toxoplasmosis or listeriosis. GBS is associated with lymphocytic infiltration (if treated).

Autopsy exam is a necessity for a trainee anatomic pathologist to pass the final exam, but it is quite a pain to study for it.  I found some brief notes (and possible exam questions) to survive the exam. Assessment: History Gross findings Dissect all organs Make sure dissection area is clean. Cause of death and correlation. How does one diagnose pneumothorax on autopsy? Dissect out the circle of Willis. How to measure ventricular thickness. Answer: 1 cm below the atrioventricular valve How to differentiate between kidney abscess and pyonephrosis. Kidney abscess is usually located at the renal cortex. How to take swabs (from any sites) How to take blood samples. Answer: from femoral vein or right atrium. How to take urine sample. Answer: suprapubic Spleen may also show hyaline arteriosclerosis, like kidneys (hypertensive change). Renal papillary necrosis is common in diabetes mellitus. ARDS (adult respiratory distress syndrome) is a manifestation of ...

Lentigo maligna Basically, lentigo maligna has increase in melanocytes.  Morphologically, melanocytes has cytoplasmic halo while basal cells do not have halo.  However, melanocytes may pass melanin to basal cells, causing confusion.  Therefore to disprove lentigo maligna, one has to do S100 IHC stain. Junctional and compound naevus DO NOT DIAGNOSE IN ADULTS, therefore treat with suspicion. The differential here will be superficial melanoma or melanoma in situ.

Venous congestion is a feature of acute inflammation rather than chronic inflammation. HMWCK (CK5/6) will stain more for carcinoma if LMWCK (for example, CK MNF 116) unable to pick up for the carcinoma.

Foamy macrophages may be seen in FSGS (focal segmental glomerulosclerosis)

What clinical information is important in medical renal biopsy? Renal profile UFEME Antibody screen Urine protein or protein-creatinine index (PCI) Glomerular count

In giant cell tumour of bone, what we will see is: 1. Multiple numerous nuclei within cell  with ill-defined border (in other words, multinucleated cell)      usually more than 10 nuclei; usually 50-100 nuclei 2. Mixture of multinucleated cells with neoplastic mononuclear cells 3. Mitosis rarely seen, with no atypical forms seen. Whereas for aneurysmal bone cyst (a potential differential diagnosis), what we will see is: Lumen containing blood surrounded by bone and collagen.

1. MPO (myeloperoxidase) 2. CD117 3. Glycophorin 4. CD34

Hodgkin lymphoma Useful stains are: CD3 CD20 CD15 CD30 PAX5 (fainter than reactive B cells; membrane staining) Hodgkin lymphoma vs anaplastic large cell lymphoma (ALCL) Hodgkin lymphoma: Scattered large cells. ALCL: More clustered formation, mixture of small and large cells.

I have found a note that I have made during a lymphoma talk at Sabah by Dr Ahmad Toha.  Here is the gist of it. About Lymphoid Follicles There are two types of lymphoid follicles: one is primary and another is secondary lymphoid follicle. Primary lymphoid follicle: dark blue in colour, stain less with Ki-67 proliferative index marker. Secondary lymphoid follicle: has paler areas, stain more with Ki-67 proliferative index marker. Useful markers for lymph nodes: CD20: germinal centre and mantle cell. CD79a: stronger staining at the mantle zone. BCL-2: an anti-apoptotic marker, mostly stain outside the follicle with 'sprinkle' of positive cells inside the follicle.  These positive cells inside the follicles are T-helper cells. CD21: identify the nodular appearance of the follicles. Ki-67 BCL-6: germinal centre CD10: germinal centre IgD: stain outside the germinal centre (?mantle zone) About Thymus: 1. Paracortex Densely cellular Located beneath cortex, at c...

We had some interesting cases shown to Prof Dr Tan PH from SGH, and received a nice tutorial from her in return :). 1. Papillary lesion In a papillary lesion, one should use more than one myoepithelial marker.  The myoepithelial markers potpourri: p63, HMWCK (either CK 5/6 or CK14), SMA. Pitfall in papillary lesion: secretory cells may have aberrant p63 expression. Neoplastic (and suspicious) papillary lesion will exhibit clonal proliferation.  ER is preferably used: diffuse positivity will suggest clonal proliferation, whereas intraductal papillomas will usually exhibit patchy ER positivity.  PR may be used in conjunction with ER but the staining is more heterogeneous, therefore it may be confusing to identify clonal proliferation by using PR immunohistochemical stain. HER-2 immunohistochemical stain is used only if there is invasive disease, and not really used to establish clonality. Encapsulated papillary carcinoma is more expansile and bulging compared to...