Milton R. Okun

Pseudolymphomatous reaction to tattoos. Report of three cases.

Three cases with pseudolymphomatous hypersensitivity reaction to tattoo pigment are described. One of the cases showed histologic features of Spiegler-Fendt pseudolymphoma. Awareness of this type of reaction to tattoo pigment can help prevent erroneous diagnosis of lymphoma. Several published reports are cited in which pseudolymphomatous reaction to tattoo pigment was erroneously diagnosed as lymphoma.

Systematic underreporting of cutaneous malignant melanoma in Massachusetts: Possible implications for national incidence figures

An independent tabulation of incidence of cutaneous malignant melanoma in Massachusetts indicates that 12% and perhaps as many as 19% of new cases of cutaneous malignant melanoma in Massachusetts are not recorded in the Massachusetts Cancer Registry, significantly more than the expected 5% (p = 0.0001). The increasing number of nonhospital medical settings in which melanomas can be diagnosed and/or treated appears to account for this discrepancy. We suspect that these findings in Massachusetts also apply to cancer reporting systems in other regions of the United States. We suggest that the true incidence of cutaneous malignant melanoma in Massachusetts, and perhaps in the United States, may be significantly higher than reported.

Histochemical differentiation of peroxidase-mediated from tyrosinase-mediated melanin formation in mammalian tissues

SummaryPreincubation with the copper-chelator, sodium diethyldithiocarbamate (DDC) and the presence of catalase in the incubation media allowed an accurate and reproducible differentiation of the role of tyrosinase from that of peroxidase in the oxidation of tyrosine and dopa in melanocytes, mast cells and eosinophils. These studies indicated that mammalian peroxidase in melanocytes, mast cells and eosinophils can mediate the conversion of tyrosine to melanin in the presence of dopa co-factor, as well as the conversion of dopa to melanin. With the methods employed, there was no evidence that tyrosinase in the preparations studied had significant ability to mediate the oxidation of tyrosine to melanin (even in the presence of dopa co-factor), although there was abundant evidence that it can mediate the conversion of dopa to melanin. Mammalian peroxidase may have roles in initiating melanin synthesis and catechol amine synthesis in vivo.

An ultrastructural study of balloon cell nevus(Relationship of mast cells to nevus cells)

Ultrastructural examination of a balloon cell nevus confirmed previous findings that balloon cells form by progressive vacuolization of melanocytes and nevus cells. Most granules of non‐vacuolated nevus cells were round, membrane‐bound structures with a uniform particulate matrix. Early changes leading to the formation of vacuoles in epidermal melanocytes included enlargement of melanosomes with separation of their fibers. Early changes leading to formation of vacuoles in dermal nevus cells included microvacuole formation in nevus granules and diffuse loss of particulate matrix. Loss of particulate matrix allowed visualization of discrete ellipsoid melanosomes in some nevus granules. Some of the epidermal balloon cells were keratinocytes. These may have developed by transfer of altered melanosomes from keratinocytes. Numerous mast cells were present; some of these showed cytoplasmic vacuoles and granules with microvacuoles. This observation, as well as the presence of ultrastructural intergrades betwten mast cells and nevus cells, supports the proposal that mast cells and nevus cells (as well as melanocytes) are histogenetically related.

Peroxidase-dependent oxidation of tyrosine or dopa to melanin in neurons.

SummaryPeroxidase activity was demonstrated in guinea pig frontal lobe by histochemical methods, and was correlated with peroxidase-dependent enzymatic synthesis of melanin from tyrosine or dopa. Peroxidase activity and peroxidase-dependent melanin synthesis appeared to be mainly in lysosomes of neurons. These findings open the possibility that peroxidase may have a role in catecholamine, lipofuscin and neuromelanin synthesis in the brain.

Apocrine adenoma versus apocrine carcinoma: Report of two cases

Two examples of apocrine neoplasm are presented, contrasting the features of an apocrine adenoma with those of a possible apocrine adenocarcinoma. Apocrine adenocarcinoma, distinct from Pagets disease, is a rare neoplasm. Its recognition is complicated by long periods of benign growth and by subtle histologic differences from apocrine adenoma.Two examples of apocrine neoplasm are presented, contrasting the features of an apocrine adenoma with those of a possible apocrine adenocarcinoma. Apocrine adenocarcinoma, distinct from Pagets disease, is a rare neoplasm. Its recognition is complicated by long periods of benign growth and by subtle histologic differences from apocrine adenoma.

Latency of the dopa reaction in mast cells.

SummaryLight microscopic observations of normal rat peritoneal mast cells and ultrastructural observations of human mast cells from lesions of nodular mastocytosis indicated that structural damage results in a pronounced increase in percentage of cells with a positive dopa reaction. Recent studies have indicated that the dopa reaction in mast cells is peroxidase-dependent. Enhancement of the dopa reaction by structural damage (latency) is probably related to increased substrate-enzyme interaction. Ultrastructural localization of dopa melanin to mast cell granules and the high percentage of mast cells showing a positive dopa reaction after structural damage is evidence against the possibility that dopa melanin is formed in mast cells by phagocytized enzyme.

DOPA compared with dihydroxyfumarate as co-factor in peroxidase-mediated oxidation of tyrosine to melanin

SummaryDihydroxyfumarate was used as a co-factor in the histochemical demonstration of peroxidase-mediated oxidation of tyrosine to melanin in eosinophils, mast cells, melanoma cells and neurons. The use of dihydroxyfumarate as co-factor provides a direct method for demonstrating peroxidase-mediated oxidation of tyrosine to melanin in tissues, and allows for the ultrastructural localization of this pigment.

Combined melanocytoma-mastocytoma in a case of nodular mastocytosis

A patient with long-standing nodular mastocytosis developed a slate-blue lesion on the scalp which produced symptoms of histamine release on mechanical and thermal stimulation. Light and electron microscopic examination of the lesion showed zones of mast cells and zones of melanized cells. A transition zone showing cells with dual (melanosomal and mast) granulation, as well as granules representing intergrades between classical mast granules and melanosomes, was present. Features of this lesion add to the accumulated evidence that there is a histogenetic relationship between mast cells and melanocytes.

Purification of peroxidase by isoelectric focusing. Use of ultrastructural localization of immunoglobulins.

Abstract Ampholine isoelectric focusing has been used to rapidly purify commercially available peroxidase preparations. Increased specific enzyme activities and increased A 412 nm to 280 nm ratios suggest that peroxidases of highest purity can be obtained by this method. Utilization of purified peroxidase-coupled anti-IgG reagents for ultrastructural localization of immunoglobulins indicate that non-specific reactions are minimized while peroxidase labeling efficiency is enhanced.