Malignant transformation of craniopharyngioma in an infradiaphragmatic case

Till now, 13 cases of malignant craniopharyngioma (CP) have been reported around the world, including 11 cases of transformation from benign tumors and 2 cases of congenital ones. Irradiation seemed to contribute a lot to the cellular transformation. The controversies about the radical surgery or irradiation have not ceased for many decades. In this article, we report a case of infradiaphragmatic CP (Id-CP) in a child who experienced almost all current treatments. However, after multiple tumor recurrences, finally the malignant transformation occurred. The analysis of the tumor regrowth pattern and clinical characteristics provided some clues to standardize and individualize the treatment of Id-CP. A 21-year-old patient was presented to our department in 2009 with complaints of severe headache, dizziness, and significantly decreased vision of the left eye. MRI indicated that the predominant solid tumor was located in the sellar region. Laboratory examination showed panhypopituitarism. Since 1998, when he was 8 years old, the patient underwent various treatments, including subtotal tumor removal (STR), gamma knife (2004), cystic fluid drainage followed by P32 intracystic irradiation (2006), and two gross total tumor removals (GTR, 2007 and 2008). After the first STR, the patient was totally blind in right eye and suffered from severe growth retardation. His body mass index (BMI) increased constantly and hormone levels decreased significantly (Figure 1 and Table 1). Pathological examination of tumor in 1998 revealed components of a typical adamantinomatous CP. However, the surgical specimens in 2007 showed prominent change in contrast; there was a resemblance in some areas to small-cell undifferentiated carcinoma, which showed appreciably high proliferative ability, which indicated possible irradiationinduced malignancy changes.Figure 1. A:: BMI and the endocrinological data of the patient. B: MRI images of tumor growth at different periods (the upper figure: before individual treatment; the lower figure: after treatment). C: Presurgical MRI images (upper figure) when presenting in our hospital in 2009. Postsurgical MRI images (lower figure) indicated GTR.Table 1: The treatment history and clinical manifestationThe tumor was again radically removed in March 2009 via the right frontotemporal approach in our hospital. Postsurgical pathologic detection indicated that the number of stellate reticulum cells significantly decreased while the palisading epithelium cells were proliferating rapidly and presenting pseudo-stratified epithelium. The cellular alignment was extremely irregular. In the region of interest, cellular atypical and karyokinesis can be identified. Tumor cells were positive for Ki-67 (++, 18%), p53 (++), p63 (+), and VEGF (+), but negative for AFP, β-HCG, and progesterone receptors. The pathological findings indicated more invasive features and malignant transformation. The final diagnosis was malignant CP. After surgery, proved by contrasted T1 MRI, the tumor was totally removed. The left lateral wall of the 3rd ventricular floor and neurohypophysis were preserved. The water-electrolyte imbalance and diabetes insipidus coexisted, but could be well controlled. Prednisone and levothyroxine sodium tablets were used to substitute the hormone deficit. The visual acuity of his left eye increased, and headache and dizziness, were significantly relieved. During 1-year follow-up, the visual acuity of his left eye improved significantly. In addition, his height increased 4 cm from 168 to 172 cm. The BMI decreased slowly to 37.5. However, in May of 2010, rechecked MRI indicated a microlesion inside the pituitary fossa. Seven months later, the lesion was proved to progress slightly. After discussion, the transsphenoidal approach was selected to resect the tumor. During the operation, the remnant of Rathke's cleft was observed being close adherence to the recurrent tumor. Tumor was totally removed as proved by postsurgical MRI. The patient's optical vision was increased after surgery. Then, during the 3 years of follow-up until January of 2014, no tumor recurrence was observed. As the endocrinological concerns, the patient constantly underwent hormone substitution therapy because of the panhypopituitarism. He could independently cope with his daily life, use computer, and intermittently went to school without significant cognitive disorder, but limited energy restricted some outdoor activities. Since 1950, 13 cases of malignant CP were reported worldwide,1 Except two de novo cases, the other 11 patients with malignant transformation from benign CP, had exclusively undergone radiotherapy and suffered from multiple recurrences. These data indicated the correlation of the CP's malignant transformation with non-GTR plus following irradiation. Likewise, the patient of this article underwent STR and partial tumor removal (PTR) surgeries and was followed by gamma knife and intracystic irradiation. After many recurrences, the malignant transformation was proved. The case supports the conclusion of Ishida et al that irradiation can induce CP's malignant transformation. Moreover, these cases might hint a viable therapeutic strategy for CP. The controversies about treatments of CP have been with us for some time. GTR was ever thought the best way to cure this kind of lesion. However, severe hypothalamic reaction could justify PTR followed by irradiation therapy. With increased comprehension, individualized treatment has been proposed according to the tumor's growth patterns.2 Our recent article3 proposed that suprasellar arachnoid and diaphragm always enveloped Id-CP with the ability to ensure GTR and protect infundibulo-tuberal part. Being a typical example in this article, MRI in 1998 indicated a case of childhood Id-CP being totally covered by diaphragm. However, the subsequent STR (1998), gamma knife (2004), and intracystic irradiation (2006) destroyed the surgical interface. As a result, the recurrent tumor protruded through the surgical corridor as proved by MRI of 2006. In addition, as shown in Figure 1A, the BMI increased significantly from 2002 to 2006. Moreover, it seemed not to decrease the tumor's recurrence. All the above data hinted that STR plus radiotherapy might not be a good choice, even though it was commonly thought as being the major element to cause tumor's malignant transformation. In spite that several papers had reported the better outcome of irradiation, no such reports focused specially on the Id-CP. For such instances, we permitted that for infundibulo-tuberal CP, which may entail more surgical difficulty and more severe hypothalamic reaction, the irradiation might be a useful alternative. However, because of related easier surgery for GTR, we suggested that the Id-CP should undergo more radical surgery. The key procedure is the removal of the intrasellar part of the tumor. Our previous paper4 indicated that a membranous septation exists between Rathke's pouch and posterior lobes of the pituitary gland, which provides a surgical interface to protect the neurohypophysis. During the last transsphenoidal surgery, the remnant of Rathke's cleft was observed with close relationship to the recurrent tumor. By total removal of this part, during 3 years of follow-up, the patient was free of tumor recurrence. Our case indicated that with careful and detailed understanding of the anatomical composition of pituitary fossa, the total excision of Id-CP should be the primary goal, and the radiosurgery should not be regarded as the first choice.