4 February 2021: Textbook Updates

We have posted updates of the following topics:

Autopsy & forensics > Types of injuries > Forensic entomology
by Lance Van Truong, D.O., Priya Banerjee, M.D.
Topic summary: Study of insects / arthropods pertaining to its applications to medicolegal and criminal death investigations. Tissue destruction and lesions caused by postmortem insect feeding activity may resemble or obscure antemortem injuries. Not all forensically important insects wait until death to feed; medical conditions and wounds can produce chemoattractants and provide substrates for necrophagous insects to feed. Insect feeding activity can modify decomposition process; activity and metabolism in a maggot mass create heat, accelerating both the decomposition process and the rate of feeding activity. A multidisciplinary approach is recommended in death investigation; collection of insect evidence and workup is best conducted in collaboration with forensic entomology technicians or forensic entomologists.

Breast > Infectious > Sparganosis
by Rebecca Czaja, M.P.H., M.D., Julie Jorns, M.D.
Topic summary: Parasitic zoonosis caused by spargana, the plercercoid tapeworm larvae of the genera Spirometra. Infection occurs by drinking contaminated water, eating raw frogs or snakes or applying raw frog or snake poultices to wounds. Most cases of human infection have been reported out of east and southeast Asian countries. Common sites are the superficial soft tissue and muscle. Presents with localized erythema or slowly growing, itchy, nodules in the breast. Incubation period is typically 6 – 11 days but may take several years to present symptoms. Prognosis is dependent on the site of infection. Complete surgical removal of superficial sparganum is the most effective therapy.

CNS tumor > Sellar region tumors > Pituitary adenoma
by Michael Punsoni, M.D.
Topic summary: Neuroendocrine tumor of the anterior pituitary gland composed of secretory cells with pituitary hormone production. Routine assessment of histology includes determination of mitoses, pleomorphism, giant cells, inclusions, inflammatory changes, stroma, hemorrhage and vascular features. Mainly fourth to seventh decade; women have slightly greater incidence. Majority occur in sella turcica within the adenohypophysis / anterior pituitary lobe. Endocrine factors may induce cell proliferation: excess production of hormones (e.g. growth hormone, corticotropin or gonadotropin). Surgical approaches to treatment are: via transsphenoidal route (minimally invasive); transfrontal approach for larger adenoma; partial versus gross total resection.

CNS tumor > Embryonal tumors > Medulloblastoma > SHH activated
by John DeWitt, M.D., Ph.D.
Topic summary: Embryonal tumor of the cerebellum with molecular evidence of SHH pathway activation and an intact TP53 locus (2016 WHO definition). TP53 wildtype tumors largely show a bimodal age distribution with cases most common in infants and young adults. Cerebellum; can involve both the hemispheres or vermis with site of origin possibly age dependent. High proportion of TP53 mutant cases contain germline TP53 mutations (Li-Fraumeni syndrome) suggestive of a causal role. Patients often present with signs and symptoms of increased cranial pressure secondary to obstruction of cerebrospinal fluid (CSF) flow from a large mass impinging on the fourth ventricle. TP53 mutated tumors typically have a much worse outcome. SMO inhibitors can be used in SHH activated medulloblastomas that are susceptible (those harboring SMO or PTCH1 mutations).

Kidney tumor > Benign adult tumors > Adult cystic nephroma
by Bonnie Choy, M.D.
Topic summary: Uncommon multilocular cystic tumor without a grossly appreciable solid component; classified as part of mixed epithelial and stromal tumor (MEST) family. Mainly occurs in adult women with peak incidence around 50 – 60 years. Noncommunicating cysts lined by single layer epithelium separated by septa with hypocellular fibrous to hypercellular spindle cell stroma. Located at poles of kidney, close to hilum or closely associated with pelvicalyceal system. Possible role of hormones in pathogenesis. Diagnosis by histologic examination of tissue. Mostly benign with rare local recurrence reported. Treatment involves nephron sparing surgery whenever feasible.

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