Digital constriction bands in pseudoainhum: morphological radiographic, and histological analysis

Familial ainhum: a case report of multiple toe involvement in a father and son, staging of ainhum with insight into different types of constricting bands

Ainhum, also known as dactylolysis spontanea, is a painful constriction of the base of the fifth toe, frequently followed by spontaneous amputation a few years later. The disease is often symmetrical on both the feet, but, occasionally, other toes are also affected and rarely the distal phalanx of the fifth finger. Pseudoainhum is a similar condition that occurs as a secondary event resulting from certain hereditary and nonhereditary diseases that lead to annular constriction of digits. We hereby present a case of familial ainhum in father and son with multiple toes affected, autoamputation, and more involvement of fourth toe than the fifth toe, which is a very rare finding.

Pathologic and Environmental Studies Provide New Pathogenetic Insights Into Ringtail of Laboratory Mice

Ringtail is a pathologic condition of laboratory rodents characterized by annular constrictions of the tail. Traditionally, it is classified as an environmental disorder caused by low relative humidity, but other factors (temperature, dietary deficiencies, genetic susceptibility, and caging type) have also been proposed. Twenty litters of mice with ringtail lesions occurred from September 2010 to August 2013 in a facility located in the northern Italy. Mice were maintained under controlled environmental conditions and fed a standard diet. Retrospective analysis of environmental data (relative humidity, temperature) was carried out. Gross, histopathologic, scanning, and transmission electron microscopy examination of tails and limbs was performed. The incidence of ringtail was 0.075% (20/26 800) of all weaned litters over the 3-year period of examination. Temperature and relative humidity remained within accepted limits in all cases except one. We observed annular constrictions in tail, digits of pes, crus, and antebrachium in 116 (100.0%), 47 (40.5%), 11 (9.5%), and 2 (1.7%) of 116 affected mice, respectively. Histologic and ultrastructural examination revealed abnormal keratin desquamation and presence of a keratin ring encircling the tail, causing progressive strangulation of the growing tail with subsequent compression and ulceration of underlying soft tissues, resulting in circulatory changes (edema, hyperemia, thrombosis, hemorrhages), ischemic necrosis, and eventually auto-amputation distal to the constriction. On the basis of our findings, we suggest a disorder of cornification as the primary lesion of ringtail in mice. The cause of these cases, however, remained undetermined, even though traditional etiologic factors (relative humidity, temperature, diet, caging type) were reasonably excluded.

"Pseudo" Nomenclature in Dermatology: What's in a Name?

In the bewildering array of scientific nomenclature in the medical field, it is important to use correct terminology, know their aberrations and the reason behind a specific terminology. This paper is an attempt towards compiling all the pseudo-nomenclatures coined in dermatology, in order to make it easier to retain and recollect these pseudo names, signs, morphology, diseases, and conditions. It is also imperative to know the true entities that these pseudo names masquerade as, so as to understand the explanation for assigning the term 'pseudo' to these conditions. A total of 52 pseudo-terms have been compiled here in reference to dermatology. Most of these pseudo-nomenclatures were coined due to some clinical or histopathological resemblance to the true conditions, while some were premature conclusions drawn from a flawed understanding of the basic nature of the condition. Clear understanding of each of these terms and the explanation behind them being pseudo will enable a dermatologist to avoid misdiagnosis and needless confusion.