Histopathological findings in pregnancy associated cutaneous hyperpigmentation.

Hyperpigmentation in pregnancy is a common phenomenon, experienced to some degree by up to 90% of pregnant women. It mainly involves sun-exposed areas, but it can extend to non-exposed zones. Cases with extensive hyperpigmentation are rarely reported. In this paper, we describe the case of a 30-year-old phototype V woman in her 37th week of pregnancy, who presented with brownish hyperpigmentation of the skin in extensive areas, including both axillae, the abdomen and the lowest part of the back. In the abdomen, there was a reinforcement of the hyperpigmentation through the linea nigra and the umbilicus. The hyperpigmentation affected the buttocks as well and involved the intertriginous area between them. Histopathologic analysis showed a hyperpigmented basal layer of the epidermis with no melanocytic atypia or melanocytic nests. Histochemical staining for iron did not show any deposits. Immunohistochemical studies for HMB-45, Melan A and SOX10 demonstrated an increased number of melanocytes. There was hyperpigmentation of basal layer keratinocytes. We also performed immunohistochemical stains for estrogen and progesterone receptors, which were both negative. The patient was examined 3 months after delivery, evidencing a significant clearing of the lesions.

A hypothesis on the morphologic differences between Unna and Miescher nevi on the head and neck, based on embryologic bases.

Unna and Miescher nevi show very different morphologic features. The main difference is that melanocytes involve mainly the papillary dermis in Unna nevi, whereas they widely penetrate the reticular dermis in Miescher nevi. The reason for this behavior is not totally understood, but anatomical location might play a role, since because Unna nevi are mainly found on the trunk, whereas Miescher nevi are mainly found on the face. We decided to test this hypothesis in relative easy way: dermis from the frontal, temporal, maxillary, and mandibullary regions derives from the neural crest, whereas the dermis of the parietal/occipital regions originates from the paraxial mesoderm (somites and somitomeres). Therefore, we studied the morphology of 137 acquired melanocytic nevi from the head and neck and classified their locations in 7 areas: occipital, temporal, parietal, frontal, face, high neck, and low neck. From such areas, we distinguished 4 groups: area A (parietal + occipital + low neck); area B (face + temporal + frontal + high neck); area 1 (parietal and occipital); and area 2 (temporal and frontal). In region A, 97.30% of the nevi were of Unna type. In region B, 89.00% were of Miescher type. Region A had 76.60% of Unna type nevi, whereas region B had 98.89% of Miescher nevi. In area 1, 100% of the nevi were of Miescher type. In area 2, 86.67% of the nevi were of Unna type. Region 1 had 86.67% of the cranial Unna nevi, whereas region 2 had 100% of the cranial Miescher nevi. Moreover, 90.9% of the nevi from the low neck were of Unna type. In the high neck, 20% of nevi were of Unna type. Finally, 90.90% of Unna nevi were in the low neck, whereas 80% of Miescher nevi were in the high neck. We concluded that these findings supported the hypothesis that the embryologic differences of these areas of head and neck might play a role in the morphology of Unna and Miescher nevi.

Subacute cutaneous lupus erythematosus in a patient with rheumatoid arthritis.

A 51-year woman with a seropositive rheumatoid arthritis (RA) developed antiLa/SSB antibodies and erythematosquamous lesions on her upper back. The histological diagnosis was subacute cutaneous lupus erythematosus (SCLE) (papulosquamous form). There was no indication or a drug-induced SCLE. The concurrence of RA and SCLE seems to be rare. We review the clinical, serologic and immunogenetic features in these patients with coexistent RA and SCLE.