Division of Otolaryngology, Sendai Municipal Hospital, Sendai, Japan.
Eur Arch Otorhinolaryngol. 2013 Sep;270(10):2729-36. doi: 10.1007/s00405-013-2392-5. Epub 2013 Feb 14.
An asymptomatic transsphenoidal meningoencephalocele was discovered incidentally by fiber laryngoscopic examination in a 62-year-old man suffering from hoarseness due to dysplasia of the vocal cord epithelium. To provide a better understanding of the pathogenesis of this anomaly, we performed histologic observations of paraffin-embedded specimens of 42 human fetal heads at 12-16 weeks of gestation. At these stages, ossification had started in the clivus but the sphenoid sinus was not developed. In contrast to the very low incidence of the intra- or trans-sphenoidal remnant of Rathke's pouch after birth, we found (1) the typical mid-line cleft of the sphenoid body in two specimens (2/42 or 4.8 %) and (2) a duct-like, sellar inferior protrusion ending in the sphenoid body in 12 specimens (12/42 or 28.6 %). The cyst-like structure in the protrusion (two specimens) seemed to be composed of obstructed veins. The intra- and trans-sphenoidal anomalies were observed more frequently in specimens without ossification of the sphenoid body than in those with ossification. However, irrespective of ossification, a cyst-like remnant of the most upper part of Rathke's pouch was always seen between the anterior and posterior lobes of the developing pituitary gland. In addition, the bursa pharyngea was seen in four specimens and we confirmed that the notochord was attached to the bursa in each case. The consistent remnant of the intrasellar Rathke's pouch appeared to explain the high incidence of Rathke's cleft cyst in adults. The relatively high incidence of intrasphenoidal anomalies in fetuses (14/42) suggested that the intra- or trans-sphenoidal remnant of Rathke's pouch was physiologically closed by ossification of the sphenoid body.
一名 62 岁男性因声带上皮发育不良而出现声音嘶哑，在纤维喉镜检查中意外发现无症状性经蝶脑膜脑膨出。为了更好地了解这种异常的发病机制，我们对 42 例 12-16 周妊娠的人胎头颅进行了石蜡包埋标本的组织学观察。在这些阶段，斜坡已经开始骨化，但蝶窦尚未发育。与出生后颅咽管囊的内或经蝶窦残留的极低发生率相比，我们发现：（1）2 例（2/42 或 4.8%）标本存在典型的蝶骨体中线裂隙；（2）12 例（12/42 或 28.6%）标本存在类似导管样、蝶鞍下突出，止于蝶骨体。突出部的囊状结构（2 例）似乎由阻塞的静脉组成。在无蝶骨体骨化的标本中，观察到的内蝶窦和蝶窦异常比有骨化的标本更频繁。然而，无论骨化与否，在发育中的垂体前叶和后叶之间，总是可以看到颅咽管囊最上部的囊状残留。此外，我们还观察到了 4 例咽囊，并且在每例标本中均确认了脊索与咽囊的附着关系。因此，鞍内的颅咽管囊残留似乎可以解释成年人中颅咽管裂囊肿的高发生率。胎儿中蝶窦内异常的相对高发率（14/42）表明，颅咽管囊的内或经蝶窦残留是通过蝶骨体的骨化而生理性关闭的。
