Pathology Outlines

CD Markers
CD99

Topic Completed: 1 February 2002

Minor changes: 3 September 2019

Revised: 14 December 2018, last major update February 2002

Copyright: (c) 2002-2018, PathologyOutlines.com, Inc.

PubMed Search: CD99 [title]

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Table of Contents

Cite this page: Pernick N. CD99. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/cdmarkerscd99.html. Accessed August 14th, 2020.

Definition / general

Also called MIC2, O13, T cell surface glycoprotein E2
Encoded by pseudoautosomal gene on short arms of X and Y
Part of Xg blood group system (NCBI)
Functions: cell surface glycoprotein involved with
1. Differentiation of primitive neuroectodermal cells (Exp Mol Med 2003;35:438)
2. Apoptosis of T cells (FEBS Lett 2003;554:478)
3. T cell adhesion
4. Migration of leukocytes
5. In Ewing / PNET, may promote growth and migration of tumor cells via downregulation of KCMF1 (potassium channel modulatory factor), a possible metastasis suppressor gene (Oncogene 2006;25:2795)
Associated with EWS-FLI1 fusion transcript, t(11;22)(q24;q12), causing FLI-1 protein overexpression

Interpretation

Distinct membranous staining for Ewing / PNET; cytoplasmic for other tumors

Uses by pathologists

Relatively nonspecific marker for Ewing sarcoma and T cell lymphoma, but does distinguish Ewing from neuroblastoma (Hum Pathol 1993;24:880)
Also distinguishes meningeal hemangiopericytoma (CD99+) from anaplastic meningiomas (CD99 weak / focal / negative, Hum Pathol 2004;35:1413)
Detect minimal residual disease by CD99+ flow cytometry in TALL (Leukemia 2004;18:703)
Anti-CD99 antibody may have therapeutic value (Eur J Cancer 2006;42:91)

Microscopic (histologic) images

Images hosted on other servers:

Ewing / PNET:

Bone

Cavernous sinus

Gallbladder

Lung

Prostate

Stomach

Site unknown

Leukemia / lymphoma:

AML

AML-M0

AML-M3

Other images:

Adult granulosa cell tumor, ovary

Ectopic hamartomatous thymoma

GIST vs. solitary fibrous tumor

Solitary fibrous tumor, larynx

Solitary fibrous tumor, ear

Spindle cell epithelioma of vagina

Synovial sarcoma, lung

Positive staining - normal

Endothelial cells, ependymal cells, hepatocytes, gastric foveolar epithelium, immature (cortical) thymic lymphocytes (Am J Surg Pathol 1995;19:1115), ovarian granulosa cells, pancreatic islet cells, Sertoli cells, T cells and activated B cells (J Korean Med Sci 1999;14:600)

Positive staining - disease

Ewing sarcoma / PNET:
- 100% (Am J Surg Pathol 2005;29:1025); membranous staining (Mod Pathol 2006;19:659), including tumors of kidney (Am J Surg Pathol 2002;26:320), pancreas (Am J Surg Pathol 2002;26:1040), skin (Am J Surg Pathol 1998;22:310), vulva/vagina (Int J Gynecol Path 2000;19:103); initial report (Am J Surg Pathol 1994;18:486)
Leukemia / lymphoma:
- Acute lymphoblastic lymphoma (B and T, Am J Clin Pathol 2001;115:11, J Korean Med Sci 2005;20:952), anaplastic large cell lymphoma (50%), other lymphomas (occasionally), acute myelogenous leukemia/chloroma (50%, Arch Pathol Lab Med 2006;130:153, Mod Pathol 2000;13:452), leukemia cutis (Mod Pathol 1997;10:283)
Other:
- Adamantinoma of ulna (Clin Orthop Relat Res 2003;408:256)
- Angiomatoid MFH (Hum Pathol 1999;30:1336)
- Atypical fibroxanthoma (73%, Am J Clin Pathol 2002;117:126)
- Breast metaplastic carcinoma (Histopathology 2001;39:578)
- Calcifying aponeurotic fibroma (Hum Pathol 1998;29:1504)
- Cervicovaginal myofibroblastoma (Pathology 2005;37:144)
- Desmoplastic small round cell tumor (23%, Am J Surg Pathol 2002;26:823)
- Ectopic hamartomatous thymoma (Arch Pathol Lab Med 2003;127:e378)
- Endometrial stromal tumors with sex cord differentiation
- Ependymoma (diffuse, strong membranous staining with intracytoplasmic dots, Appl Immunohistochem Mol Morphol 2001;9:125)
- Epithelioid sarcoma (proximal type - 25%, Mod Pathol 2001;14:655)
- Extrarenal malignant rhabdoid tumor
- Gastric carcinoma, intestinal type (some, J Korean Med Sci 2002;17:483)
- Gastrointestinal stromal tumor (Arch Pathol Lab Med 2002;126:1189)
- Giant cell angiofibroma (Am J Surg Pathol 2000;24:971)
- Hemangiopericytoma (meningeal, lipomatous, Hum Pathol 2000;31:1108)
- Hepatocellular carcinoma (Indian J Path Microbiol 2003;46:625)
- Malignant fibrous histiocytoma (35%, J Cutan Pathol 2006;33:24)
- Melanoma (60%, J Cutan Pathol 2006;33:663)
- Merkel cell carcinoma of skin (crisp membranous staining, Appl Immunohistochem Mol Morphol 2000;8:37)
- Mesenchymal chondrosarcoma (Hum Pathol 1996;27:1273)
- Neuroendocrine tumors (Virchows Arch 2000;437:270)
- Nuchal fibromas
- Ovarian sex cord stromal tumors (most, Am J Surg Pathol 2005;29:143, Arch Pathol Lab Med 2000;124:563)
- Ovarian surface epithelial tumors, carcinoids and Wolffian tumors (various)
- Pancreatic endocrine neoplasms (50%, Histopathology 2004;45:384)
- Perineuroma (myxoid sclerosing type)
- Pleomorphic hyalinizing angiectatic tumor (focal, Path Int 2002;52:664)
- Pulmonary pleomorphic (sarcomatoid) carcinoma (J Korean Med Sci 2005;20:50)
- Retinoblastoma (focal in 30%, Ann Diagn Path 2001;5:148)
- Rhabdomyosarcoma (15 - 25%, Oral Oncol 2002;38:450; Am J Surg Pathol 2002;26:1175)
- Sclerosing perineuroma (60%, Am J Surg Pathol 1997;21:1433)
- Sinonasal undifferentiated carcinoma (14%, Am J Surg Pathol 2001;25:156)
- Skin solitary sclerotic fibroma (J Cutan Path 2003;30:631)
- Solitary fibrous tumor: myxoid, Mod Pathol 1999;12:463, oral soft tissue, Am J Surg Pathol 2001;25:900, thyroid gland, Am J Surg Pathol 2001;25:1424, atypical / malignant tumors - 60%, Am J Surg Pathol 1998;22:1501
- Spindle cell epithelioma of vagina (Arch Pathol Lab Med 2001;125:547)
- Superficial acral fibromyxoma (Hum Pathol 2001;32:704)
- Synovial sarcoma (90 - 100%, all types, Am J Surg Pathol 2002;26:1434)
- Testicular sex cord stromal tumors (variable, Hum Pathol 2000;31:1055)
- Uterine tumors resembling ovarian sex cord tumors (57%, Am J Surg Pathol 2002;26:403)
- Wilm tumors (some)

Negative staining

Clear cell sarcoma, myelodysplastic syndrome, neuroblastoma (children, Am J Surg Pathol 1998;22:327, adults, Am J Surg Pathol 2001;25:918; olfactory, Am J Surg Pathol 1998;22:391, Hum Pathol 1995;26:639), small cell carcinoma, smooth muscle tumors, squamous cell carcinoma of skin, thymic carcinoma (Am J Surg Pathol 1997;21:936), Wilm tumor

Additional references

Am J Surg Pathol 2002;26:1040 (PNET - pancreas), Mod Pathol 2002;15:673 (PNET - dura), OMIM 313470