Yasuo Tanita

A rapidly growing pigmented nail streak resulting in diffuse melanosis of the nail. A possible sign of subungual melanoma in situ

Subungual melanomas are one of the most common types of malignant melanoma among the Japanese population. Although most pigmented nail streaks are benign and remain unchanged in their color and shape for a long time, rarely are they precursor lesions of subungual melanomas, i.e., a rapid growing pigmented nail streak resulting in diffuse melanosis of the nail is thought to be an early stage of subungual melanoma in situ. We found four patients with these changes; three of these patients were children. The lesions occurred on the right index finger, right thumb, left middle finger, and right great toe, respectively. A slightly haphazard combination of colors ranging from dark brown to black, the important characteristic of subungual melanoma in situ, was observed in two cases. In the remaining two cases, although the haphazard combination of colors was not distinctive, many fine, dark, longitudinal lines were seen within diffuse, light‐brownish pigmentation. Serial histologic examination of the excised tissue specimens showed great proliferation of vacuolated melanocytes with variable nuclear atypicality along the entire basal layer in all cases. These histologic changes were compatible with those of atypical melanocytic hyperplasia or intraepidermal melanoma (in situ melanoma), which is an early lesion of subungual melanoma. An adult case is thought to be a definite example of a subungual melanoma in situ. We also made the diagnosis of melanoma in situ in the remaining three cases of children with rapidly growing pigmented nail streaks because their histopathologic features were distinguishable from those of the adult case. However, there remains some hesitation about this because invasive subungual melanoma is rare in children.

Improvement in survival rate of patients with acral melanoma observed in the past 22 years in Sendai, Japan

While the incidence of malignant melanoma is much lower in Japanese than in Caucasians, the commonest site of melanoma in Japanese has been reported to be the acral regions of the limbs. The survival rate for acral and nodular melanoma observed at the Department of Dermatology, Tohoku University Hospital in Sendai, Japan from 1969 to 1990 was reviewed. Among 150 melanoma patients 125 (83%) and 17(11%) had primary cutaneous melanoma and mucous membrane melanomas, respectively. Frequent sites for cutaneous melanomas were the sole (31%) and subungual regions (15%). Comparison of the stages of plantar melanoma at diagnosis showed that the proportion of stages III and IV decreased after 1980 with a corresponding increase in those with a tumour thickness of less than 4 mm (stage II). Concurrently, the prognosis of plantar melanoma has improved; the 5‐year survival rate in each of the three periods 1969–75, 1976–80 and 1981–85 was 21, 70 and 90%, respectively. This was also the case with subungual melanoma. Such improvements in the prognosis are thought to be mainly due to early detection through the growing public awareness of this life‐threatening disease.

Palpation of the skin with a robot finger: an attempt to measure skin stiffness with a probe loaded with a newly developed tactile vibration sensor and displacement sensor

Background/aims: Various attempts have been made to measure mechanical properties of the skin quantitatively and noninvasively. However, no attempt has been made to measure a tactile sense of our finger that palpates the skin; when we palpate the skin to search for any change, we at first rub the skin surface softly with a finger tip to detect a surface change and then press the finger against the skin to perceive any alteration in consistency. The problem here is how to record such tactile sense quantitatively, because the palpating examination for smoothness or softness of the skin totally depends on a subjective perception. A new tactile sensor from robot technology is equipped with a fingertip‐like sensing probe oscillating at a resonant frequency of 60 kHz; it is capable of clearly sensing small differences in hardness of solid substances from a change in the oscillating frequency and from a displacement sensor that detects depressability of the skin. We have used this new measuring system to evaluate the hardness and elasticity of skin.

PIGMENTED FRECKLES ON THE SOLE AS ACRAL LENTIGINOUS MELANOMA IN SITU

We report a rare case presenting a very early, non‐invasive stage of acral lentiginous melanoma (ALM). A 67‐year‐old male patient came to our clinic 4 days after he noticed the presence of a pigmented lesion on the sole of his right heel.

A case of fibrosarcoma in a child.

昭和63年1月28日生まれの女児。出生時より, 左臀部の一部に, 多毛とその周囲の皮膚に紅斑, および硬結を触れた。生後5ヵ月を過ぎた頃から, その部分よりもやや前方が, 淡紅色の紅斑を伴って隆起してきた。そして1ヵ月後には, 高さ5cm, 直径12cm大の腫瘤性の病変を形成した。術前の生検よりの診断では, infantile fibromatosisのaggressive typeであったが, 手術標本を検討してinfantile fibrosarcomaと診断した。