STAT6-positive intraorbital papillary tumor: a rare variant of solitary fibrous tumor?
We experienced a peculiar case of orbital mesenchymal tumor in a 22-year-old Japanese woman. The tumor showed a papillary proliferating pattern, but no typical hemangiopericytomatous staghorn vessels. The tumor was composed of round to oval shaped cells with oval nuclei and mild nuclear atypia. Abundant vascular cores were present in the central portion of papillary proliferations of tumor cells. Immunohistochemistry revealed that the tumor cells were positive for CD34 and bcl2. Moreover, they showed positive nuclear signals of STAT6, which have recently been shown to be specific for solitary fibrous tumors. In the literature, only one case of solitary fibrous tumor with papillary and retiform growth pattern has been reported, but the case partially showed the typical staghorn vessel pattern. Although the definite diagnosis is difficult in the settings of the unusual histology and the deficiency of NAB2-STAT6 fusion, it is possible that this STAT6-positive intraorbital papillary tumor is a very rare variant of solitary fibrous tumor.
Department of Surgical Pathology, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 663-8501, Japan. Electronic address: tsuka-y@hyo-med.ac.jp.
Yoshitane
Y
Tsukamoto
Department of Surgical Pathology, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 663-8501, Japan.
Takahiro
T
Watanabe
Department of Plastic Surgery, Hyogo College of Medicine, Nishinomiya, Japan.
Soh
S
Nishimoto
Department of Plastic Surgery, Hyogo College of Medicine, Nishinomiya, Japan.
Masao
M
Kakibuchi
Department of Anatomic Pathology, Pathological Sciences, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
Yuichi
Y
Yamada
Department of Anatomic Pathology, Pathological Sciences, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
Kenichi
K
Kohashi
Department of Anatomic Pathology, Pathological Sciences, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
Yoshinao
Y
Oda
Department of Surgical Pathology, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 663-8501, Japan.
Seiichi
S
Hirota
D014408:Biomarkers, Tumor / Q000032:analysis*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D009918:Orbital Neoplasms / Q000378:metabolism / Q000473:pathology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D050800:STAT6 Transcription Factor / Q000096:biosynthesis*; D054364:Solitary Fibrous Tumors / Q000378:metabolism / Q000473:pathology*; D055815:Young Adult
D014408:Biomarkers, Tumor; D050800:STAT6 Transcription Factor; C494101:STAT6 protein, human
Papillary growth; STAT6 nuclear signal; Solitary fibrous tumor