Tumor size is an important prognostic factor for MMBC, and the diameter of the largest deposit provides a better fit in a multivariate model for OS than aggregate diameter and aggregate volume. Therefore, tumor size in MMBC should continue to be measured using the diameter of the largest deposit.

We present a case of a 49-year-old man who presented with a solitary atypical pigmented lesion with a surrounding halo of dermatitis. Dermoscopy showed a pigment network at the periphery with areas of scar-like depigmentation, negative pigment network and erythema. The lesion was treated preoperatively with a potent topical corticosteroid resulting in a reduction of inflammation. Histology showed an early Clark level 1 melanoma arising within a severely dysplastic compound melanocytic naevus. There was an adjacent perivascular chronic inflammatory cell infiltrate with occasional eosinophils. Minimal, though definite spongiosis with parakeratosis was also present. The scar was subsequently re-excised achieving appropriate excision margins for melanoma in situ. Six months later, there was recurrence of dermatitis at the scar with no evidence of recurrent melanoma. To our knowledge, melanoma with Meyerson phenomenon has not been reported in the literature. This case highlights that all lesions should be evaluated on clinical and dermoscopic grounds regardless of the presence or absence of eczema. Our case adds yet another entity that may display Meyerson phenomenon and consequently a halo of eczema cannot be considered a reassuring sign when evaluating melanocytic lesions.

Panniculitis, inflammation of the subcutaneous fat, is a relatively uncommon condition that usually presents with inflammatory nodules or plaques. Erythema nodosum (EN) is clinically the most frequent form of panniculitis and is considered a reactive process that may be triggered by a wide variety of stimuli. Whilst up to 55% of EN is considered idiopathic, the most common causes include infections, drugs, systemic illnesses such as sarcoidosis and inflammatory bowel disease, pregnancy, and malignancy. EN typically presents in the teens and 20s, and is seen more commonly in females. It is often preceded by a nonspecific prodrome of one to three weeks, which may include fever, malaise, and symptoms of an upper respiratory tract infection. Cutaneous lesions then follow, typically localized on the extensor aspect of the limbs. The lesions are painful rounded or oval, slightly raised, non-ulcerative red nodules. The exact pathogenesis of EN is not understood, although is thought to result from deposition of immune complexes in the venules of the septae in subcutaneous fat, causing a neutrophilic panniculitis. The classical histopathological picture is of a septal panniculitis without vasculitis. However, the pathological features vary with the chronology of the lesions. Even without specific therapy for a causative condition, EN typically resolves without treatment. Therefore, symptomatic support is adequate for the majority of patients.

We report a patient with Type 2 diabetes mellitus complicated by neuropathy affecting the phrenic nerves, resulting in fatal respiratory failure. Diabetic mononeuropathy is common and usually recovers spontaneously, but bilateral phrenic nerve involvement appears to be uncommon and difficult to treat. The pathology of diabetic mononeuropathy is not well understood and we believe this to be the first histological report of a phrenic nerve biopsy in this condition.

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