The epidemiology of neonatal tumours. Report of an international working group

Human placenta: a human organ for developmental toxicology research and biomonitoring

Pregnant mothers are exposed to a wide variety of foreign chemicals. This exposure is most commonly due to maternal medication, lifestyle factors, such as smoking, drug abuse, and alcohol consumption, or occupational and environmental sources. Foreign compounds may interfere with placental functions at many levels e.g. signaling, production and release of hormones and enzymes, transport of nutrients and waste products, implantation, cellular growth and maturation, and finally, at the terminal phase of placental life, i.e. delivery. Placental responses may also be due to pharmaco-/toxicodynamic responses to foreign chemicals, e.g. hypoxia. On the other hand, placental xenobiotic-metabolizing enzymes can detoxify or activate foreign chemicals, and transporters either enhance or prevent cellular accumulation and transfer across the placenta. The understanding of what xenobiotics do to the placenta and what the placenta does to the xenobiotics should provide the basis for the use of placenta as a tool to investigate and predict some aspects of developmental toxicity. This review aims to give an update of the fate and behavior of xenobiotics in the placenta from the viewpoint of xenobiotic-metabolizing enzymes and transporters. Their response levels will be described according to gestational status and methods used. The effects of foreign chemicals on placental metabolizing enzymes will be discussed. Also, interactions in the transporter protein level will be covered. The role of the placenta in contributing to developmental effects and fetotoxicity will be examined. The toxicological effects of maternal medications, smoking, and environmental exposures (dioxins, pesticides) as well as some possibilities for biomonitoring will be highlighted.

From the Archives of the AFIP

Fetal tumors are a diverse group of neoplasms, which are unique in their histologic characteristics, anatomic distribution, and pathophysiology. The biologic behavior of tumors in the fetus may differ dramatically compared with that of the same tumor detected later in life. Teratomas are the dominant histologic type and constitute the majority of both extracranial and intracranial neoplasms. Although often histologically mature, they may prove lethal because of their location and metabolic demands on the fetus. Large solid tumors may lead to cardiovascular compromise and hydrops fetalis. Extracranial teratomas are most commonly located in the sacrococcygeal area, followed by the head and neck, chest, and retroperitoneum. Fetuses with intracranial tumors have a poor prognosis regardless of histologic type. There are, however, two notable exceptions: lipomas and choroid plexus papillomas, both of which have a more favorable outcome. Neuroblastoma is the most common fetal malignancy. It may be either solid or cystic and is more often located on the right side. It typically has favorable biologic markers and stage at presentation. The prognosis for prenatally diagnosed cases is excellent. Other fetal neoplasms include soft-tissue tumors (both benign and malignant), leukemia, mesenchymal hamartoma of the kidney, and liver tumors (hemangioendothelioma, mesenchymal hamartoma, and hepatoblastoma).

Congenital peripheral primitive neuroectodermal tumor refractory to treatment

The authors report an unusual case of an infant presenting with a congenital peripheral primitive neuroectodermal tumor (PPNET) of the left hand refractory to treatment. A newborn girl was born with a large bluish-red mass of 4.5 cm diameter protruding into the palm and the dorsum of the left hand. Tumor biopsy confirmed the diagnosis of PPNET. The initial metastatic workup for the detection of metastases was negative. Four cycles of chemotherapy according to CCSG 7881/POG 8850 regimen B were given. Despite this aggressive chemotherapy the tumor grew to involve the entire left hand. The left hand was amputated, and then two cycles of topotecan/cyclophosphamide were given. Five months later extensive metastases developed, involving the brain, lungs, liver, and skeleton, and the child died at the age of 2.5 years. PPNET presenting at birth is uncommon; presentation in the hand is unusual, and the fact that it did not respond to treatment is still more uncommon.

The approach to the patient with a difficult melanocytic lesion

Although most histological diagnoses are made with relative ease and with great specificity and reproducibility, there is a subset of cases in which a specific and reproducible diagnosis is difficult or even impossible to render. In the melanocytic system, these cases can be divided into two broad categories. The first category, 'superficial atypical melanocytic proliferations of uncertain significance' (SAMPUS), includes predominantly junctional melanocytic proliferations, and melanocytic proliferations that are confined to the epidermis and papillary dermis, without evidence of tumorigenic proliferation or mitotic activity there. The prognosis for cure of these lesions is excellent if they are completely excised. Such lesions may include, for example, dysplastic naevi, Spitz naevi or pigmented spindle cell naevi with a few atypical melanocytes above the dermal-epidermal junction, or with greater than average cytological atypia, or with mitoses, where the differential diagnosis of melanoma in situ is difficult or impossible to rule out. The other category, 'melanocytic tumours of uncertain malignant potential' (MELTUMP), is comprised of melanocytic proliferations that form tumours in the dermis, and are therefore potentially capable of metastasis. Examples of such lesions may include atypical Spitz naevi, deep penetrating naevi, possible naevoid melanomas, or cellular blue naevi, where because of increased mitotic activity or cytologic atypia, a diagnosis of invasive or tumorigenic melanoma cannot be ruled out. In managing such lesions, we follow two main principles. The first is to manage each lesion with therapy designed to be adequate for management of the most significant consideration in the differential diagnosis. The second principle is to make clinicians and patients specifically aware of the diagnostic difficulty in their lesion, so that management can be undertaken on a true informed consent basis.