[Cutaneous melanoma; diagnostic procedures and their evaluation in diagnosing and mapping sentinel nodes. Part 2].

The second part of this review describes the advantages, and evaluates the radionuclide-guided methods for sentinel lymph node localization and also evaluates the intraoperative application of the blue dye technique in melanoma. By combining the two techniques, the detection rate rises to 96%-98%. The presence of cancer cells in the sentinel node is histopathologically shown by using hematoxylin-eosin and by using sensitive techniques for the detection of micrometastases. Immunohistochemical tech-niques specific for epithelial markers and polymerase chain reaction examination are also applied. Sentinel lymph node biopsy suggests whether regional elective lymphade-nectomy shall be performed.

[Cutaneous malignant melanoma; diagnostic procedures and their evaluation in diagnosing and mapping sentinel nodes].

Cutaneous malignant melanoma represents 4% of all the malignant neoplasms. Nevertheless, 79% of the fatal malignant skin diseases are attributed to melanoma. In melanoma patients, the most important prognostic factor is the regional lymph node invasion. The present article describes the classical diagnostic, staging and therapeutic strategies in melanoma patients. In the realm of cutaneous melanoma, pre-operative lymphoscintigraphy and the intra-operative gamma-probe detection, removal and biopsy of the sentinel lymph node(s), comprise convenient, procedures, virtually lacking morbidity. The definition of sentinel includes the first lymph node or nodes, draining the lymph from the primary lesion, thereby attributed with the highest probability of harbouring migrating metastatic cells. A sentinel lymph node negative for malignancy accurately "predicts" the absence of melanoma cell invasion in all the rest regional and distant lymphatic basins. The method aims in the best discrimination of high-risk patients, as candidates for selective lymphadenectomy, with or without adjunctive treatment. Radionuclide-guided lymphatic mapping and surgery is based on the phagocytosis of colloidal-based radiopharmaceuticals by the macrophages encountered in functional tumour-infiltrated sentinel nodes. The nuclear methods successfully add to the staging and the potential surgical treatment of the disease.

Erdheim-Chester disease: symmetric uptake in the (99m)Tc-MDP bone scan.

Erdheim-Chester disease (E-C D) is a rare clinicopathologic entity with nearly pathognomonic radiographic features. About half of the affected exhibit extraskeletal manifestations, including involvement of the hypothalamus-pituitary axis, lung, heart, retroperitoneum, skin, liver, kidneys, spleen and orbit. This disease usually affects individuals in their fifties to their seventies and has a male preponderance. The lesions of E-C D consist of lipid-storing CD68 (+) and CD1a (-) non-Langerhans cell histiocytes, either localized to the bone or involving multiple systems of the body as well. Skeletal involvement is characteristically bilateral and symmetric, exhibiting an osteosclerotic pattern in the metaphysis and diaphysis of the long bones, usually sparing epiphysis. We recently had a 68 years old male patient with E-C D, with a mild and persistent knee pain, who was subjected to a 3-phase technetium-99m methylene diphosphonate ((99m)Tc-MDP) bone-scan and subsequently to gallium-67 citrate ((67)Ga-C) whole body scan. The characteristic symmetric pattern of these scans raised the question of E-CD disease. The patient showed an excellent symptomatic response to high-dose steroids. However, the symptoms recurred after discontinuation of treatment.

Trapping of technetium-99m albumin macroaggregate and other four radiopharmaceuticals by blood clots in vitro.

Radiopharmaceuticals are known to interact with the blood components (i.e. the red blood cells, serum proteins etc) but so far, there have been no data regarding their purely mechanical trapping in thrombi. The experiments presented in this communication provide evidence that the technetium-99m labeled albumin macroaggregate ((99m)Tc-MAA), apparently due to its particle size, can be almost quantitatively retained in the in vitro model described. These results can be extrapolated in vivo and offer a plausible explanation for either the "hot spot" artifact, occasionally seen in lung perfusion imaging or for the partial trapping of (99m)Tc-MAA by a thrombus at the tip of a subclavian catheter, as has been recently reported. Control experiments were also run using (99m)Tc-methylene diphosphonate ((99m)Tc-MDP), (99m)Tc(III)-dimercaptosuccinic acid ((99m)Tc(III)-DMSA), (99m)Tc-methoxyisobutyl isonitrile ((99m)Tc-MIBI) and sodium pertechnetate (Na(99m)TcO(4)), in order to study the extent of trapping of these radiopharmaceuticals under identical incubation conditions. (99m)Tc-MDP and (99m)Tc(III)-DMSA exhibited the lowest blood clot uptake (partially non-specific and partially mechanical trapping), while in the case of (99m)Tc-MIBI and Na(99m)TcO(4), besides mechanical and non-specific clot-trapping, transport and retention inside the red blood cells was also observed.

Jaw uptake of technetium-99 methylene diphosphonate in patients on biphosphonates: a word of caution.

Nitrogen-containing biphosphonates are a group of medications that are increasingly used in the management of Paget's disease, fibrous dysplasia, osteoporosis, multiple myeloma and metastatic prostate or breast cancer bone disease. On 2004 it was established that nitrogen-containing biphosphonates may induce jaw osteonecrosis and since then, a substantial number of publications has supported this finding. Jaw osteonecrosis may be asymptomatic, lasting for about a year or symptomatic, accompanied with mild or severe pain. Jaw osteonecrosis usually results in patients with poor dental hygiene, or subjected to invasive dental procedures. Its incidence increases with the length of nitrogen-containing biphosphonates treatment and appears to be higher for the Zometa(TM) users. It is important to early recognize this entity, since early intervention can make a significant difference to the outcome of this debilitating side effect. We here report three patients who had a positive technetium-99m methylene diphosphonate ((99m)Tc-MDP) bone scan. One of these patients also had osteomyelitis and was treated aggressively. The other two were treated in a more conservative manner. Detailed dental examination supported the scintigraphic findings. Biopsy was performed only in one patient and also offered specimens for antibiotic cultures. In discussion, jaw biopsy is a debatable procedure in the setting of jaw osteonecrosis and many consider that it should be avoided in most cases, except if it is necessary to establish the diagnosis and suggest antibiotic treatment by obtaining samples for bacterial cultures. Although axial tomography and magnetic resonance imaging are useful in defining the extent of the disease, 3-phase (99m)Tc-MDP bone scan is the most sensitive imaging modality pinpointing the disease at its early stages. In conclusion, a 3-phase (99m)Tc-MDP scan with anterior and lateral views of the skull is indicated in all symptomatic or asymptomatic patients, with a history of long-term nitrogen-containing biphosphonate treatment, since this may lead to an early detection of the disease.

A large intra-atrial thrombus detected during a lung perfusion scan with technetium-99m macroaggregated albumin injected through the subclavian venous line.

A sixty five year old female patient carrying a double lumen subclavian catheter, with severe right-sided heart failure, was subjected to lung perfusion scan in order to rule out pulmonary embolism. Administration of Tc-99m macroaggregate albumin ((99m)Tc-MAA), via a double lumen (Hickman) subclavian line, resulted in trapping almost half of the injected dose in the right atrium, at the tip of the subclavian catheter. There was no evidence of pulmonary embolism. This finding was interpreted as consistent with the presence of a large intra-atrial thrombus. This thrombus, despite the thrombolytic treatment that followed, was detached and caused cardiac arrest and eventually the death of the patient. Autopsy showed a massive pulmonary embolus. This report suggests, that injecting (99m)Tc-MAA for a lung perfusion study via the central venous line, may result in the early detection of a thrombus, as in this case at the tip of the catheter and this may be life saving for the patient. We have been unable to find in the literature a similar case of a thrombus detected by the iv administration of (99m)Tc-MAA.

The role of 99mTc(V)-DMSA scan as compared to 99mTc-MDP and CT scans in imaging the primary tumor and metastases of osteosarcoma.

The oncophilic complex of technetium-99m labeled pentavalent dimercaptosuccinic acid (99mTc(V)-DMSA) has been successfully used for the detection of primary and metastatic medullary thyroid cancer and for imaging various soft tissue tumors like lung, brain and prostate cancer. In this article, the role of 99mTc(V)-DMSA in the diagnosis of the primary tumor and metastases of osteosarcoma patients as compared to the 99mTc-MDP scan and the CT scan was studied. Twenty-eight patients with bone disease were referred to the Nuclear Medicine Department of Saint Savas Oncology Hospital in Athens from the Orthopedics Department of the same Hospital. From them, 18 (Group A) had osteosarcoma, 7 (Group B) osteomyelitis and 3 (Group C) bone fractures. The final diagnosis was made after fine needle aspiration biopsy. All patients were subjected to the 99mTc(V)-DMSA scan, the standard bone scan (99mTc-MDP) and CT scan. Group A patients showed a selective uptake of 99mTc(V)-DMSA in the primary tumor region. No abnormal 99mTc(V)-DMSA uptake was observed in the patients of Groups B and C. The 99mTc(V)-DMSA scan was found to be superior to the 99mTc-MDP and the CT scans in identifying metastases of osteosarcoma. Sensitivity was 100%, 86% and 98% respectively.