The aim of this study was to investigate the morphology, molecular phenotypes, distribution and developmental history of interstitial neurons in the human corpus callosum, here defined as intracallosal neurons. We analysed 26 fetuses, three newborns, five infants and children, and eight adults [age range - 15 weeks postconception (PCW) to 59 years] by means of acetylcholinesterase (AChE) histochemistry and immunohistochemistry for neuron markers (MAP2, NeuN, NPY, calretinin and calbindin). We found a heterogeneous neuron population, positioned within the callosal trunk itself (aside from neurons present in the transient midline structures such as callosal sling, septa or subcallosal zone), which was most numerous during the second half of gestation and early postnatal years. We named these cells intracallosal neurons. At 15 PCW, the intracallosal neuron population consisted of poorly differentiated, small fusiform or bipolar, migratory-like MAP2- or calretinin-positive neurons which could be observed until mid-gestation. Later the population comprised morphologically diverse, predominantly well-differentiated MAP2-, NPY-, calbindin- and AChE-positive neurons. The morphological differentiation of intracallosal neurons culminated in the newborns and remained pronounced in infants and children. In the adult brain, the intracallosal neurons were found only sporadically, with small somata and poorly stained dendrites. Thus, intracallosal neurons form part of a transitory neuron population with a developmental peak contemporaneous to the critical period of callosal formation. Therefore, they may be involved in processes such as axon guiding or elongation, withdrawal of exuberant axons, fasciculation, or functional tuning, which occur at that time.

While early 1990s reports showed the phosphorylation pattern of fetal tau protein to be similar to that of tau in paired helical filaments (PHF) in Alzheimer’s disease (AD), neither the molecular mechanisms of the transient developmental hyperphosphorylation of tau nor reactivation of the fetal plasticity due to re-expression of fetal protein kinases in the aging and AD human brain have been sufficiently investigated. Here, we summarize the current knowledge on fetal tau, adding new data on the specific patterns of tau protein and mRNA expression in the developing human brain as well as on change in tau phosphorylation in the perforant pathway after entorhinal cortex lesion in mice. As fetal tau isoform does not form PHF even in a highly phosphorylated state, understanding its expression and post-translational modifications represents an important avenue for future research towards the development of AD treatment and prevention.

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Anogenital warts (condyloma acuminatum or venereal warts) are a common sexually transmitted disease in males and females. Common clinical treatment of anogenital warts is conservative, however, in extreme cases conservative therapy is insufficient and surgical excision is required. Giant condyloma acuminata (Buschke-Löwenstein tumour) is an extremely rare clinical type of genital wart, characterised by aggressive down growth into underlying dermal structures. A 55-year-old female presented with cauliflower-like growth over the anogenital and sacral region, earlier diagnosed as condyloma acuminatum which was resistant to conservative therapy. During the period between 2005 and 2008 the patient underwent five surgical procedures. Due to the size and location of the tumour, gynaecological and plastic surgeons were involved in the procedures. In addition, definitive histology examination identified a superficial vulvar carcinoma.