Strong desmin expression in a congenital desmoplastic infantile ganglioglioma mimicking pleomorphic rhadomyosarcoma: a case report including ultrastructural and cytogenetic evaluation and review of the literature.
OBJECTIVE
Desmoplastic infantile gangliogliomas (DIGs) are rare tumors of infancy. Herein, we describe an unusual case of DIG diagnosed by prenatal ultrasound.


METHODS
This 5-day-old newborn was delivered after a prenatal ultrasound revealed a large cystic mass in the left cerebral hemisphere along with an echogenic solid component.


RESULTS
The tumor revealed a glial and neuronal proliferation in a background of desmoplasia more typical of DIG and a minor component with a more primitive, immature appearance to the glioneuronal elements. A significant component of the tumor was composed of pleomorphic eosinophilic spindle cells in whorls and interlacing fascicles that showed a strong, sharp, and diffuse positivity for desmin, thus mimicking rhabdomyosarcoma. However, the tumor cells were GFAP (+), INI-1 (+), and myogenin (-). Mitoses were seen both in the more spindle cell astroglial areas as well as the more primitive neuroepithelial cells. The MIB-1 proliferation index was brisk, exceeding 15 %, and in areas it was estimated to be as high as 30 %. Such high proliferation index has been described and accepted in the more primitive neuroepithelial areas, but not in the terminally differentiated, spindle cell astroglial areas as in our case. Our patient was incidentally diagnosed prenatally. To our knowledge, this case is the first documented congenital DIG diagnosed prenatally.


CONCLUSIONS
This case highlights the pitfalls in diagnosing DIG, which can mimic a rhabdomyosarcoma. Furthermore, it underscores the importance of re-evaluating the grading of these tumors or at least segregating the variants where the prognosis may be more guarded.
Department of Pathology and Laboratory Medicine, Mount Sinai Medical Center, 4300 Alton Rd., Blum Bldg. Rm. 2400, Miami Beach, FL 33140, USA. dr_saraalghamdi@yahoo.com
Sarah
S
Alghamdi
Amilcar
A
Castellano-Sanchez
Carole
C
Brathwaite
Taiyo
T
Shimizu
Ziad
Z
Khatib
Sanjiv
S
Bhatia
D002585:Cesarean Section; D003582:Cytogenetics; D003893:Desmin / Q000096:biosynthesis* / Q000235:genetics; D003937:Diagnosis, Differential; D018303:Ganglioglioma / Q000175:diagnosis / Q000378:metabolism* / Q000648:ultrastructure; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007150:Immunohistochemistry; D007231:Infant, Newborn; D019394:Ki-67 Antigen / Q000032:analysis; D008279:Magnetic Resonance Imaging; D008297:Male; D008854:Microscopy, Electron; D009457:Neuroglia / Q000473:pathology / Q000648:ultrastructure; D009474:Neurons / Q000473:pathology / Q000648:ultrastructure; D011379:Prognosis; D012208:Rhabdomyosarcoma / Q000175:diagnosis* / Q000648:ultrastructure; D015173:Supratentorial Neoplasms / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000378:metabolism*; D016216:Ultrasonography, Prenatal
D003893:Desmin; D019394:Ki-67 Antigen