View source for Cytologically Yours: Unknowns: 201401: Case 2

==Clinical History==
52 year old female with a pancreatic head mass.

==Cytology==
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===Resident Questions===
* <spoiler text="Diagnosis?">__NOGLOSSARY__
* Pancreatic Endocrine Neoplasm
** Include Islet cell tumor and pancreatic carcinoid tumors
** Approximately 5% of pancreatic neoplasms
** Most commonly seen in both male and female adults between 40-60 years old but can occur at any age
** Small (1-5 cm) well circumscribed lesion may look cystic on imaging
** Commonly seen in the tail of the pancreas
** Can be part of Multiple Endocrine Neoplasia-1, von Hipple-Lindau disease, Neurofibromatosis type 1, Tuberous Sclerosis Complex
</spoiler>
* <spoiler text="What are some of the cytologic features that lead you to the diagnosis?">__NOGLOSSARY__
* Cellular smear with singly dispersed uniform cells
* Loosely cohesive or discohesive uniform cells
* Cells are uniform, plasmacytoid with abundant finely granular cytoplasm
* Background is clean
* Occasional pleomorphism can be seen
* Round/oval bland cells with salt and pepper chromatin
</spoiler>
* <spoiler text="Differential diagnosis?">__NOGLOSSARY__ 
* Acinar cell carcinoma
** Clusters, acinar groups and single cells with abundant granular cytoplasm and prominent nucleoli
** Lack salt and pepper chromatin
** Positive staining for trypsin, chymotrypsin and alpha-1-antichymotrypsin
** Negative for neuroendocrine markers
* Solid Pseudopapillary Neoplasm
** May see hyaline globules and clear cytoplasmic vacuoles
** Branching papillary clusters with distinct central fibrovascular cores, but this can be seen in PEN too
** Positive for vimentin, CD10, beta catenin, neuron specific enolase, CD56
** Negative for keratin markers
* Plasmacytoma
** Look for a perinuclear hof and clock face chromatin
** Positive staining for CD138
** Negative for neuroendocrine markers
* Islet cell hyperplasia
** Difficult/ impossible to distinguish from islet cell tumor by cytology alone
* Melanoma
** Can see melanin pigment in the cytoplasm but not always
** Melanoma cytomorphology can be quite diverse
** Positive for MART-1, HMB45, MITF
** Negative for neuroendocrine markers
</spoiler>
*<spoiler text="What ancillary studies would you order?">
* Neuroendocrine markers
** CD56
** Synaptophysin
** Chromogranin
* Cytokeratin
* TTF-1
* Markers specific to peptide production 
</spoiler>

{{Cytologically Yours}}

[[Category:Unknowns]]