Submitting Author: Yu, Shan-Chi, MD
Institution: National Taiwan University Hospital
Additional authors:Jia-Hau Liu, Ming Yao
Session: Extramedullary manifestations of myeloid neoplasms

The patient was a 33-year-old woman with acute myeloid leukemia, FAB M2, normal karyotype. Her initial presentation was fever and cough, and laboratory test revealed blasts in the peripheral blood. She underwent I3A7 induction chemotherapy, and achieved the first complete remission. An early relapse developed after consolidation chemotherapy with I2HDAC and N2HDAC. She underwent HDAC plus VP16 chemotherapy, and achieved the second complete remission. She received allogeneic sibling peripheral blood stem cell transplantation, and there was no evidence of relapse until 3 years later.

Bilateral temporal visual field defect was noted 3 years after peripheral blood stem cell transplantation. She also complained of breast swelling, galactorrhea and body weight gain. Head computed tomography in outside hospital showed a 2-cm pituitary tumor. Due to rapid deterioration of her visual filed defect, she was admitted to our hospital for surgery. Neurological examination showed bilateral temporal hemianopsia. The right side was worse than left side. Her complete blood count was: Hb 10.7 g/dL, MCV 94.3 fL, Plt 266 K/μL, WBC 6.92 K/μL. Differential count showed no blast in the peripheral blood. Hormone studies showed elevated serum prolactin (49.3 ng/mL). Magnetic resonance image showed a 2-cm mass in the sellar fossa with suprasellar extension. She underwent craniotomy and tumor excision, and myeloid sarcoma was diagnosed. Cerebrospinal fluid examination showed leukemic involvement with numerous abnormal myeloblasts. The bone marrow biopsy and aspiration revealed no evidence of leukemic involvement.

After the operation, she received radiotherapy and intrathecal chemotherapy, but her central nervous system disease was refractory. After courses of FLAG chemotherapy, she achieved the third complete remission and underwent the second allogeneic sibling peripheral blood stem cell transplantation. Central nervous system relapse developed later. Fungal pneumonia and fungemia complicated, and she died of septic shock and multiple organ failure.

During operation, the surgeon found that the tumor had involved suprasellar space, sellar fossa and right optic canal. The optic chiasm and right optic nerve were compressed by tumor.

Intraoperative imprint cytology (Liu’s stain, a modified Romanowsky stain) of pituitary tumor showed numerous abnormal blasts with disperse chromatin, large prominent nucleoli, occasional nuclear convolution or identation, and lightly blue cytoplasm. Promyelocytes with granulated cytoplasm were also noted. Small amount of maturing granulocytes were present. Intraoperative frozen section (H&E stain) showed sheets of mononuclear cells replacing pituitary parenchyma. A minority of cells contained eosinophilic granules in the cytoplasm.

The tumor excised, around 2 cm in size, was vaguely lobulated, soft in consistency, and white in color. Microscopic examination (H&E stain) showed extensive infiltration of atypical mononuclear cells among lymphoid follicles. The atypical cells contained medium-sized convoluted nuclei, fine chromatin and small distinct nuclei. Most these atypical cells had scare cytoplasm. Eosinophilic granulated cytoplasm was present in a minority of them.

Immunohistochemistry: CD45(+), CD43(+), CD34(-), CD117(+), MPO(-), CD68(-), CD3(-), CD79a(-), CD20(-), TdT(-)

Not performed

1. Pituitary myeloid sarcoma is very rare. The case presented with typical manifestations of pituitary adenoma, including neurological deficit and hormone effect. Imprint cytology was of great help for the intraoperative diagnosis of myeloid sarcoma.

2. Isolated central nervous system relapse after peripheral blood stem cell transplantation is rare. Notably, the relapse after the second transplantation was exclusively in the central nervous system, too.

Pituitary myeloid sarcoma, a relapse of acute myeloid leukemia after peripheral blood stem cell transplantation

Additional immunohistochemical stains performed by the consensus group:

CD11c: positive
CD33: subset positive
Lysozyme: negative

Acute myeloid leukemia, relapsing only as a pituitary mass (myeloid sarcoma) after stem cell transplantation

Case 68