Bone formation in chondrodermatitis nodularis helicis

Chondrodermatitis nodularis

Chondrodermatitis nodularis is a common condition in clinical practice but rarely discussed or reported in the literature. It most often affects the helices and antihelices of the ear. It is either uni- or bilateral. Injury usually initiates or triggers the disease. Microscopic pathology supplements the clinical diagnosis. Its etiopathogenesis points to this being a transepidermal elimination or perforating dermatoses.

Neural hyperplasia in chondrodermatitis nodularis chronica helicis

BACKGROUND

Chondrodermatitis nodularis chronica helicis (CNCH) is a common condition characterized by tender nodules of the helix, of uncertain mechanism. The pain is not explained by current physiopathological hypotheses.

OBJECTIVE

We sought to investigate possible nerve hyperplasia in CNCH.

METHODS

Thirty-seven cases of clinically typical CNCH were submitted to conventional microscopy after surgical excision and analyzed with immunohistochemistry using PS100 and neurofilament antibodies. As controls, we investigated 25 tumors of the ear with the same methods.

RESULTS

Large nerves (>0.1 mm in diameter) were seen in 8 of 37 cases; these were close to the cartilage or at the upper part of the ulceration. Increased numbers of small nerve sections (0.01-0.06 mm in diameter) were seen in 35 of 37 cases, with more than 20 sections per low-power field in 18 cases. Nerve hyperplasia was not observed in tumors of the ear, even in ulcerated cases.

LIMITATIONS

Hypothesis based on morphologic observations.

CONCLUSIONS

Nerve hyperplasia is present in CNCH, but is often masked by intense vascular and inflammatory reactions. This finding may explain the induction of pain by light pressure, whereas ulcerated auricular malignant tumors are generally painless. Certain authors believe that CNCH is an equivalent of prurigo nodularis, which interestingly also shows nerve hyperplasia.

Auricular ossification

A patient with extensive bilateral auricular ossification presented with chondrodermatitis nodularis helicis on one side. The condition was otherwise asymptomatic. Ossification was detected on radiological and histological examination. Underlying medical conditions were not found. We believe this developed as a consequence of cold injury. Auricular ossification is an unusual cause of the so-called petrified external ear, in which the subcutaneous tissue is stony hard. It is more commonly caused by dystrophic calcification. Calcification and ossification are clinically identical and histological examination is required to definitively differentiate them.