#genpath

Papillary carcinoma of thyroid - papillary clusters, "Orphan Annie" nuclei and psammoma bodies.

Psammoma bodies are laminated, concentric, calcific spherules in papillary adenoCa of thyroid, serous papillary cystadenoCa of ovary, meningioma, and malignant mesothelioma.

Anitschkow cells - activated histocytes in Rheumatic Heart Disease

Auer rods - cytoplasmic inclusions in promyelocytic leukemia cells

Reed-Sternberg cells - binucleate or bilobed nuclei with "owl-eye" nucleoli, in Hodgkin disease

Case: 8 month-old boy with repeated pneumococcal pneumonia and low IgM, IgG, and IgA. Almost no CD19+ cells, but CD4+ and CD56+ are within normal. BM biopsy shows high #cells with cytoplasmic mu chains, but none bearing surface IgM. -->

X-linked (Bruton) agammaglobulinemia - one of the more common forms of primary immunodef.

Caused by block in B-cell maturational process due to mutations in cytoplasmic tyrosine kinase, called Bruton tyrosine kinase (btk), which is important for signals that drive pro-B cells-->pre-B cells-->mature naive B cells.

B-cell maturation stops at where heavy chain genes have been rearranged, but have not began to produce cytoplasmic mu heavy chains.

KEY: X-linked agammaglobulinemia is caused by a block in the B-cell maturation process due to mutations in btk, and B-cell maturation stops at the point and cells will not develop beyond the pt at which they can produce cytoplasmic mu heavy chains.

Adenosine deaminase deficiency --> severe combined immunodef. Causes buildup of toxic products in lymphocytes (WBC), which decreases their levels in peripheral blood. In this case, ALL lymphocyte categories would be decreased in blood.

Absence of gamma chain of IL-2 receptor --> Severe combined immunodef. Causes failure of prolif responses in both B and T cells, so both would be depressed.

CD40 ligand deficiency --> hyper-IgM syndrome, inability to switch Ig isotypes due to absence of stimulatory TH cell signal.

Bronchogenic Ca (smoking) is associated with several paraneoplastic syndromes caused by tumor release of ADH, ACTH, PTH, and VIP

Tumoral ADH --> euvolemic hyponatremia (less Na)

Central ADH secretion (SIADH) - after head trauma or brain tumor (intracranial neoplasm)

Excess water intake and paraneoplastic ADH secretion --> hyponatremia

Participate in diff path processes (e.g. atheroma formation & wound healing). They are the principal mediators of wound contraction-->aesthetic and functional deficits.

Endothelial cells --> angiogenesis (makes new blood vv) during development of granulation tissue. New vv are derived from sprouts of preexisting vv, which grow and solid buds and then remodel-->capillary tubes. Endothelial cells proliferate in response to growth factors (VEGF vascular endothelial growth factor)

Epidermal cells (aka labile cells) are continuously dividing cells that can regenerate and fill a wound defect-->negligible scarring if minimal disruption of BM and close margins. A clean surgically sutured wound is the paradigm of this "healing by first intention"-->conspicuous scar that undergoes subsequent contraction.

Large red raised lesion on infant's face that persists into adulthood --> Port-wine stain, a vascular lesion that does not regress with age (unlike strawberry nevus)Port-wine stains can be a component of Sturge-Weber disease, which includes leptomeningeal angiomatosis (vascular lesions of meninges) and sometimes cutaneous angiomatosis elsewhere

Brain CT --> hemispheric atrophy (venous infarction) with tram-track calcification along cortical ribbon

Note: Characteristic findings of Sturge-Weber Syn include a facial port-wine stain (persists into adulthood) and leptomeningeal angiomatosis (hemi atrophy and cortical calcif).

Arnold-Chiari malformations - cluster of brain/spinal cord malformations with a downward displacement of the cerebellar vermis and tonsils into F magnum

Dandy-Walker malformation - distended 4th ventricle with a hypoplastic (or absent) cerebellum

Neurofibromatosis - benign and malignant peripheral nerve lesions and cafe-au-lait spots