Alveolar rhabdomyosarcoma metastatic to the ovary. A report of two cases and a discussion of the differential diagnosis of small cell malignant tumors of the ovary

[Rhabdomyosarcoma of adult genital tract: A short review]

Rhabdomyosarcoma, most common soft tissue tumor in children, represent 8% of solid tumors in children. Conversely, in adults, this histology is very rare and no consensual recommendation is supported. If gynecological localization is one of the most frequent in children, it is a minority in adults. The management of this type of tumor is based on treatment multimodality combining surgery, chemotherapy, radiotherapy and brachytherapy. This pathological separate entity differs from other sarcomas by its greater sensitivity to chemotherapy and radiotherapy. The aim of this study is to conduct a general review of diagnostic and treatment of genital tract rhabdomyosarcoma in adults, and to report pathological characteristics of this type of tumor.

Evaluation of minimal disseminated disease in cryopreserved ovarian tissue from bone and soft tissue sarcoma patients

STUDY QUESTION

What is the risk of finding malignant cells in cryopreserved ovarian tissue from sarcoma patients?

SUMMARY ANSWER

Minimal disseminated disease (MDD) was not detected in frozen-thawed ovarian tissue from 26 patients by any of the sensitive methods applied.

WHAT IS KNOWN ALREADY

In case of leukemia, the risk of malignant cell transmission through the graft is well known and widely documented. However, for bone cancer, like Ewing sarcoma or osteosarcoma, only a small number of case reports, have been published. These cancers often affect prepubertal girls, in whom ovarian tissue cryopreservation and transplantation is the only option to preserve fertility.

STUDY DESIGN, SIZE, DURATION

The presence of malignant cells in cryopreserved ovarian tissue from patients with bone/soft tissue sarcoma was investigated with disease-specific markers for each patient, using immunohistochemistry (IHC), FISH and real-time quantitative RT-PCR (qPCR), with the original tumor serving as a positive control.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Forty-eight sarcoma patients were enrolled in the study, 12 of whom subsequently died. In each case, tissue from the primary tumor was investigated in order to identify markers (immunohistochemical and/or molecular) to analyze the ovarian tissue case by case. Ovarian tissue from osteosarcoma (n = 15), liposarcoma (n = 1) and undifferentiated sarcoma (n = 5) patients could not be evaluated, as no specific markers were detected by FISH or sensitive IHC in any of their primary tumoral tissue. One patient with Li-Fraumeni syndrome was also excluded from the study. IHC analyses were therefore performed on ovarian tissue from 26 patients and qPCR on 19. The primary tumors involved were Ewing sarcoma family of tumors (n = 14), rhabdomyosarcoma (n = 7), synovial sarcoma (n = 2), clear cell sarcoma (n = 2) and a malignant peripheral nerve sheath tumor (n = 1).

MAIN RESULTS AND THE ROLE OF CHANCE

MDD was not detected in any of the 26 analyzed samples using sensitive techniques in this largest reported series, even from patients who subsequently died and/or those who presented with metastasis (11/26), hence the most aggressive forms of bone cancer. Indeed, anti-CD99 IHC and PCR performed on patients presenting with Ewing sarcoma family of tumors (n = 14) was negative in all cases. In patients with soft tissue sarcoma (n = 12) primitive tumor markers were detected by IHC and were negative in ovarian tissue. PCR could only be performed in 6/12 of these patients, again proving negative.

LIMITATIONS, REASONS FOR CAUTION

Cryopreserved ovarian fragments to be transplanted cannot be tested, so this analysis of malignant cells cannot guarantee that all cryopreserved fragments will not contain any disseminated disease. Moreover, molecular markers are not readily available for all types of tumors.

WIDER IMPLICATIONS OF THE FINDINGS

These results are reassuring regarding the risk of malignant cells in the ovary for transplantation, as the study involves a large series including different types of sarcomas. We believe this will help clinicians in their patient counseling for fertility preservation and restoration.

STUDY FUNDING/COMPETING INTERESTS

This work was supported by the Fonds National de la Recherche Scientifique de Belgique-FNRS under Grants Nos 7.4578.14 (Télévie to MS) and 5/4/150/5 to MMD. The authors declare no competing financial interests.

Autotransplantation of cryopreserved ovarian tissue in cancer survivors and the risk of reintroducing malignancy: a systematic review

BACKGROUND The risk of recurrent oncological disease due to the reintroduction of cancer cells via autotransplantation of cryopreserved ovarian tissue is unknown. METHODS A systematic review of literature derived from MEDLINE, EMBASE and the Cochrane Library was conducted. Studies on follow-up after autotransplantation; detection of cancer cells in ovarian tissue from oncological patients by histology, polymerase chain reaction or xenotransplantation; and epidemiological data on ovarian metastases were included. RESULTS A total of 289 studies were included. Metastases were repeatedly detected in ovarian tissue obtained for cryopreservation purposes from patients with leukaemia, as well as in one patient with Ewing sarcoma. No metastases were detected in ovarian tissue from lymphoma and breast cancer patients who had their ovarian tissue cryopreserved. Clinical studies indicated that one should be concerned about autotransplantation safety in patients with colorectal, gastric and endometrial cancer. For patients with low-stage cervical carcinoma, clinical data were relatively reassuring, but studies focused on the detection of metastases were scarce. Oncological recurrence has been described in one survivor of cervical cancer and one survivor of breast cancer who had their ovarian tissue autotransplanted, although these recurrences may not be related to the transplantation. CONCLUSIONS It is advisable to refrain from ovarian tissue autotransplantation in survivors of leukaemia. With survivors of all other malignancies, current knowledge regarding the safety of autotransplantation should be discussed. The most reassuring data regarding autotransplantation safety were found for lymphoma patients.

WT1 expression in the female genital tract

The Wilms tumor gene 1 (WT1) has been reported in normal tissues and many neoplasms of the female genital tract. This review discusses WT1 expression in the female genital tract and its potential utility in the differential diagnosis of neoplasms that occur at this location. WT1 is of value in the differential diagnosis of synchronous serous carcinomas arising in the ovary/fallopian tube/peritoneum and endometrium, as strong WT1 positivity in both tumors points toward an extrauterine origin. In addition, WT1 can be used to distinguish sex cord stromal tumors (WT1 positive) from endometrioid carcinomas (OECs). WT1 expression is not helpful in the differential diagnosis of ovarian serous carcinomas (OSCs) and transitional carcinomas, as both are typically positive and has limited value in the distinction of serous tumors arising in the ovary/fallopian tube/peritoneum from mesotheliomas. WT1 is also not helpful to differentiate small cell carcinoma of hypercalcemic type from juvenile granulosa cell tumor, a common diagnostic problem. Intra-abdominal desmoplastic round cell tumor reacts to WT1 (C-terminal) in contrast to all other tumors discussed which helps to separate this rare tumor from most other small round cell tumors that may involve, primarily or secondarily, the ovary with the exception of small cell carcinoma of hypercalcemic type that typically reacts with the N-terminal of WT1.

Primary ovarian rhabdomyosarcoma in children

Although rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in children, primary rhabdomyosarcomas of the ovary are extremely rare, with only eight well-documented pediatric cases previously reported in the literature. We present two additional cases: an alveolar RMS originating in the right ovary with metastatic spread to the splenic flexure of the colon and to both lungs in a 13-year-old African American girl, and an embryonal RMS arising in the right ovary of a 6-year-old Caucasian girl with pre-operative intra-abdominal rupture and a malignant right pleural effusion. Both patients had complete resection of their primary tumors and received chemotherapy including vincristine, doxorubicin and cyclophosphamide with good response to therapy. Both are alive 8 and 9 months post-operatively.

Feasibility of ovarian tissue cryopreservation for prepubertal females with cancer

BACKGROUND

Loss of fertility is one of the long-term adverse effects of high-dose chemotherapy or total body irradiation for cancer, even in children. Ovarian tissue cryopreservation (OTC) may make it possible for survivors of childhood cancer to have children. We evaluated the feasibility of this technique for prepubertal girls.

METHODS

Between September 2000 and February 2005, 49 prepubertal girls were referred to the Reproductive Biology Unit for OTC before sterilizing treatment.

RESULTS

One ovary each was collected from 47 patients, by laparoscopy in 24 patients and laporotomy in the others. In 16 cases, the ovary was harvested during laparotomy to resect a residual abdominal tumor. No complications occurred after operations. Ovarian tissue was frozen by a slow-cooling protocol, using DMSO and sucrose as cryoprotectants. An mean of 17.6 +/- 6.5 ovarian tissue fragments was cryopreserved per patient. Follicle concentration was evaluated histologically for 46 patients and a strong correlation was found between age and follicular density. None of the cases had visible ovarian tumor components. Ovarian cryopreservation was not carried out for two patients.

CONCLUSION

The cryopreservation of ovarian tissue could be systematically offered even to prepubertal girls at risk of sterility due to gonadotoxic treatment.

From Krukenberg to today: the ever present problems posed by metastatic tumors in the ovary. Part II

This is the second of a two-part consideration of metastatic tumors to the ovary. Here, the matter is considered in 16 categories, largely site-specific. The first tumor discussed is gastric carcinoma of intestinal-type whose ovarian manifestations have been the subject of a recent paper which emphasized its differences from the Krukenberg tumor. Coverage of intestinal adenocarcinoma emphasizes the landmark 1987 paper of RH Lash and WR Hart. The section on pancreatic neoplasms reemphasizes the problems caused by metastatic ductal carcinoma, considered primarily in Part I, and discusses less common issues such as spread of neuroendocrine and acinar cell carcinomas. The limited information on spread of tumors of the gallbladder and extrahepatic bile ducts is then reviewed before more detailed consideration of hepatic neoplasms, prompted by recent contributions on hepatocellular carcinoma and intrahepatic cholangiocarcinoma, the latter based on significant experience with this problem in Thailand. The section on appendiceal neoplasms highlights ovarian spread of diverse tumors ranging from typical intestinal-type adenocarcinoma to signet-ring cell carcinomas with various patterns which in the ovary may prompt diagnoses such as a goblet cell (mucinous) carcinoid tumor, but whose ovarian features place them in the category of a Krukenberg tumor. The diverse problems in differential diagnosis of carcinoid tumor (provoked by nested, acinar, and other patterns, including folliclelike spaces) are then reviewed. The section on breast cancer emphasizes that, although usually a manifestation of late stage disease and often not bulky in the ovaries, metastatic breast cancer may form large masses which can represent the clinical presentation. That patients with breast cancer have an increased risk of primary ovarian cancer and that the latter is more common than secondary spread of breast cancer is noted. The section on lung tumors largely reflects information in a recent paper that small cell carcinoma and adenocarcinoma are the lung cancers that spread to the ovary most commonly. The extremely broad differential diagnosis posed by metastatic malignant melanoma ranging from that of an oxyphilic tumor, to a small cell tumor, to a follicle-forming neoplasm, is then considered. The sections on renal cell carcinoma and other urinary tract neoplasms emphasize the differential diagnosis of metastatic clear cell carcinoma and primary clear cell carcinoma, an issue usually resolvable by an awareness of the various features of the ovarian variant, rarely or never seen in the renal variant. The section on metastatic sarcomas discusses endometrial stromal sarcomas, gastrointestinal stromal neoplasms, and miscellaneous other sarcomas. The endometrial stromal tumors are problematic largely because the history of a primary tumor may be remote, in the ovaries the typical growth and vascular pattern of endometrial stromal neoplasms is not always conspicuous, and some endometrial stromal sarcomas in the ovary show sex cordlike patterns of growth. Recent information has indicated that gastrointestinal stromal tumors may rarely have significant ovarian manifestations and if the primary neoplasm is overlooked, the ovarian tumor may be misdiagnosed, usually as an ovarian fibromatous tumor, but potentially as another primary neoplasm. The sections on ovarian spread of uterine carcinomas emphasize the problems owing to cervical adenocarcinomas, which have a greater tendency to involve the ovaries than squamous cell carcinomas and can simulate primary mucinous or endometrioid cancers. The final neoplasms considered are malignant mesothelioma and the desmoplastic small round cell tumor. The microscopic features of malignant mesothelioma are so different from those of primary ovarian carcinoma in most instances that the diagnosis should be readily established on routine microscopic evaluation. The differential diagnosis of the desmoplastic small round cell tumor is more complex because of the greater overlap with the many other small cell malignant tumors that may involve the ovaries primarily or secondarily. Nonetheless, differences exist in most cases and awareness of the entity should lead to consideration of the desmoplastic neoplasm, particularly in a young female. In this area, as in a number of others considered in the review, immunohistochemistry may play a significant, sometimes crucial, role. However, as pointed out in brief concluding remarks, despite the aid of that modality, as in surgical pathology overall, careful consideration of the clinical background, distribution of disease, gross characteristics and spectrum of routine microscopic findings, will lead to the correct diagnosis in the majority of cases and at the very least lead to formulation of a considered differential diagnosis such that use of special techniques may be judicious and those results placed in context of the time-honored clinical and pathologic features.

Cryoconservation de cortex ovarien chez la fille prépubère : indications et faisabilité

OBJECTIVE

Survival improvement of children, adolescents and young women with cancer has led to consider with more cautiousness the long time iatrogenic side effects of treatments. Among those, premature ovarian failure has been described even for children. The aim of the study was to evaluate the indications and the feasibility of ovarian tissue cryopreservation for prepubertal girls.

PATIENTS AND METHODS

From September 2000 to December 2004, 47 prepubertal girls were referred by oncologists for ovarian tissue cryopreservation. After informed consent, the ovarian tissue was collected and frozen by a slow cooling protocol until the temperature of liquid nitrogen. A histological analysis and a follicular account were performed.

RESULTS

The harvest of ovarian tissue was performed for 45 patients. No surgical side effect occurred. The younger girls had a follicular density higher than the older. No metastatic ovarian tumour was found.

DISCUSSION AND CONCLUSIONS

Numerous arguments as the follicular density in the ovary, the age of the patient, no surgical side effect, no metastatic ovarian tumour and recent progress in term of birth after ovarian tissue autografting allowed to think it is very important and ethical to propose an ovarian tissue cryopreservation even for children before sterilising treatment.

Malignant Melanoma Involving the Ovary: A Clinicopathologic and Immunohistochemical Study of 23 Cases

Ovarian malignant melanoma (MM), primary or metastatic, is an extremely rare tumor and in the absence of a previous diagnosis can represent a diagnostic challenge. We present the clinicopathologic and immunohistochemical features of 23 cases seen in our institution over a period of 40 years (1962-2001). The patients' age ranged from 14 to 53 years (mean 35.7 years). Ethnicity was known in 19 patients: 14 white, 4 Hispanic, and 1 black. A previous history of MM was definitively obtained in 14 patients; in these cases, the interval between the primary MM and the ovarian metastasis ranged from 15 to 228 months (mean 77.7 months). The tumor was unilateral in 19 and bilateral in 4 cases. The tumor size ranged from 4.5 to 23 cm (average 10 cm); the melanoma arising in a cystic teratoma was 0.2 mm in thickness. The tumor was grossly pigmented in 8 cases (35%). The architectural pattern was nodular (8 cases), diffuse (6 cases), nodular and diffuse (5 cases), nested (3 cases), and lentiginous arising in a teratoma (1 case). Follicle-like spaces were seen in 8 cases, pseudo-glandular areas in 1 case, pseudo-myxoid areas in 1 case, and cords in 1 case. The tumor cell type was epithelioid in 19 cases, spindled in 2 cases, mixed epithelioid and spindled in 1 case, and small cell in 1 case. Nucleoli were prominent in 18 cases, and nuclear inclusions were present but rare in the majority of cases. Nuclear grooves were seen in 3 cases. Necrosis was extensive in 8 cases, focal in 10 cases, and was absent in 5 cases. In 8 cases, initial diagnoses included sex cord stromal tumor, germ cell tumor, sarcoma, or undifferentiated carcinoma. S-100 was positive in 18 of 19 cases, HMB-45 in 17 of 20 cases, MART-1 in 13 of 15 cases, tyrosinase in 10 of 15 cases, and Mitf in 8 of 14 cases. Inhibin was positive in 3 of 14 cases. Calretinin was focally positive in 1 of 12 cases. Treatment performed in 18 of the cases are as follows: oophorectomy with/without chemotherapy (10); total abdominal hysterectomy with bilateral salpingo-oophorectomy with/without chemotherapy (6); vaginal hysterectomy, bilateral salpingo-oophorectomy, and chemotherapy (1); and total abdominal hysterectomy with salpingo-oophorectomy (1). Follow-up ranging from 2 to 96 months was available in 18 patients. All but one had metastases in other organs, most often in the lungs. Thirteen patients died of disease (range 2-76 months), 3 are alive with disease (6-18 months), and 2 have no evidence of disease at 24 and 96 months; one was the patient with melanoma arising within a teratoma. In conclusion, MM involving the ovary is a rare disease, predominantly seen in women of reproductive age, and is associated with a poor prognosis. The tumor is most often metastatic from another site and is unilateral in most cases. Nodular or diffuse pattern and epithelioid cell type are most frequently seen, and the tumor can be mistaken for germ cell and sex cord stromal tumors. S-100 is the most sensitive marker. MART-1 was positive in the few cases that were negative with HMB-45. Inhibin can be focally positive in some cases.

Mesenchymal tumors and tumor-like lesions of the female genital tract: a selective review with emphasis on recently described entities

The diverse mesenchymal tumors and tumor-like lesions that occur within the female genital tract include a number of lesions that have only been recently characterized and others about which there is new information. In this group are the aggressive angiomyxoma, angiomyofibroblastoma, and cellular angiofibroma. Criteria for the distinction of these lesions are reviewed, as are the pathologic features of prognostic significance in assessing smooth muscle tumors of the vulva. The diagnostic problems that the epithelioid variant of smooth muscle tumors, both benign and malignant, may pose when they occur in various areas of the genital tract are discussed, particularly with regard to problems encountered in the ovary, a site where the diagnosis often is not considered. Recent information expanding the morphologic spectrum of fibroepithelial polyps of the genital tract is presented, and important non-neoplastic entities, including nodular fasciitis and the postoperative spindle cell nodule, are reviewed. Mesenchymal tumors of the various types seen in the soft tissues may be encountered anywhere in the female genital tract and have been the subject of particular recent interest in the ovary; issues relevant to differential diagnosis are reviewed.

Imaging features of ovarian metastases from colonic adenocarcinoma in adolescents

This paper describes the imaging features of ovarian metastases from adenocarcinoma of the colon in adolescent females. We reviewed retrospectively abdominal and pelvic computed tomographic and pelvic ultrasound examinations, histologic slices, and clinical charts of six adolescent females with ovarian metastases secondary to adenocarcinoma of the colon. One patient had ovarian metastasis at presentation and was presumed to have a primary ovarian tumor. The ovarian metastases were either solid (n = 3), complex with both solid and cystic components (n = 2), or multilocular cysts (n = 1). The ovarian lesions were large, ranging from 6 cm to 18 cm in diameter. Colorectal carcinoma in adolescent females is frequently associated with ovarian metastases. One imaging characteristic differs in adult and adolescent ovarian metastases, although they do have features in common: in adolescents, a smaller proportion of colorectal ovarian metastases are multicystic (17%) compared with the adult series (45%). These lesions are frequently large and may be complex, multicystic, or solid. Although it is a rare disease, the differential diagnosis of adnexal masses in adolescent females should include ovarian metastases from adenocarcinoma of the colon.

Ovarian small cell tumors: an electron microscopic review

Small cell tumors of the ovary are uncommon but represent an important group to recognize in the differential diagnosis of primary and metastatic ovarian neoplasms. In some cases the correct diagnosis cannot be confidently made on the basis of clinical setting, routine light microscopy, and immunohistochemistry, and electron microscopy may be supportive or definitive in establishing cell type. The cell type is often important in choosing optimal therapy and in predicting prognosis. The authors performed electron microscopy on a moderate number of ovarian small cell tumors and here describe and illustrate the diagnostic features of representative examples of various types. The ultrastructural features of the metastatic tumors, such as embryonal rhabdomyosarcoma, neuroblastoma, and melanoma, are identical to those of their respective primary tumors, are well known, and usually pose no problem in diagnosis. On the other hand, the ultrastructural features of some primary ovarian small cell tumors may present a more difficult differential diagnosis, because they have features that are subtle and/or in common. Exemplary of tumors in this category are diffuse adult granulosa cell tumor, endometrial stromal sarcoma, and small cell carcinomas of the hypercalcemic and pulmonary (oat cell) types. Distinguishing among them may be difficult but is possible, and electron microscopy may be a valuable supplement to the diagnostic information obtained from the clinical presentation, light microscopy, immunohistochemistry and, in some tumors, cytometric analysis of these neoplasms.

Ovarian metastases from cervical carcinomas other than pure adenocarcinomas. A report of 12 cases

Twelve cases of ovarian metastases from cervical carcinomas, most with clinical manifestations of ovarian involvement, are reported. The patients were 23-73 years of age (average, 43 years). The ovarian and cervical tumors were synchronous in eight patients; in three, ovarian tumors were discovered 10 months, 2.5, and 3 years after the detection of a cervical neoplasm. In one patient, the cervical tumor was not discovered until autopsy 7 months after presentation. Four patients had abdominal swelling or distention, three had vaginal bleeding, three had an abnormal Papanicolaou smear, and two had masses discovered during pelvic examination. The ovarian tumors, six of which were bilateral, ranged from 5-17 cm (average, 9.5 cm) in maximal dimension in 11 patients; in the 12th patient, the involved ovary was not enlarged. The cervical tumors were grossly evident in 10 patients. They were usually deeply invasive, often with extracervical extension. Four were squamous cell carcinomas; two, small cell carcinomas; one, a mixed small cell carcinoma and adenocarcinoma; one, a mixed poorly differentiated carcinoid and adenocarcinoma; two, adenosquamous carcinomas; one, a transitional cell carcinoma; and one, an undifferentiated carcinoma. Various features, including bilaterality of the ovarian tumors, the finding that the histologic features of the ovarian tumors typically were unusual for a primary ovarian neoplasm, and the presence of extensive extracervical disease, led to the conclusion that the ovarian tumors were metastatic from the cervix. Although ovarian metastases of cervical carcinoma are uncommon, this series illustrates that, occasionally striking examples with clinical manifestations of ovarian involvement occur.

Nonpulmonary small cell carcinomas of extragenital origin metastatic to the ovary

Seven small cell carcinomas of extragenital and extrapulmonary origin that metastasized to the ovary are described. The tumors occurred in women who were 21-77 years of age (mean, 49 years) and were discovered at, or close to, the time of presentation. The primary sites were the intestine (three cases), thymus (two cases), and inguinal skin (one case), and in one case it was undetermined. The ovarian tumors, four of which were bilateral, ranged from 1.2 to 25 cm in diameter (mean, 11 cm). Microscopic examination showed typical features of small (oat) cell carcinoma in six cases; one neoplasm resembled a small cell carcinoma of intermediate cell type and contained rare glands. On immunohistochemical examination, six of six tumors stained for cytokeratin, five of five for neuron-specific enolase, two of six for chromogranin, and none of four for vimentin. The primary cutaneous tumor was a Merkel cell carcinoma. The patient with that case died at 8 months. Two patients with intestinal tumors died at 1 and 2 months, and one is free of disease at 4 years after receiving chemotherapy. Both patients with mediastinal tumors received chemotherapy; one died at 11 months and one had brain metastases at 5 months and was lost to follow-up. The final case is recent. The differential diagnoses in these cases include primary ovarian small cell carcinomas of hypercalcemic and pulmonary types and various other small cell malignant tumors metastatic to the ovary. Consideration of a variety of clinical and pathologic features should enable these important distinctions to be made.

Metabolism of 25-hydroxyvitamin D3 to 24,25-dihydroxyvitamin D3 by blood derived macrophages from a patient with alveolar rhabdomyosarcoma during short-term culture and 1 alpha,25-dihydroxyvitamin D3 after long-term culture

We have examined the ability of blood-derived monocytes and macrophages isolated from a patient with alveolar rhabdomyosarcoma and hypercalcaemia, to form 24,25-dihydroxyvitamin D3 (24,25(OH)2D3) or 1 alpha,25-dihydroxyvitamin D3 (1 alpha,25(OH)2D3) from 25-hydroxyvitamin D3 (25(OH)D3). Adherent monocyte-macrophage cells incubated with 25(OH)D3 over the initial 2 days in culture synthesized 1.9 pmol 24,25(OH)2D3/h/incubation (representing 0.63 pmol/h/10(6) cells), whereas macrophages synthesized 1.03 and 1.15 pmol 1 alpha,25(OH)2D3/h/incubation after 1 and 4 weeks in culture respectively. In a further experiment synthesis of 1 alpha,25(OH)2D3 by long-term cultured macrophages fell from 2.25 to 0.04 pmol/h/incubation following exposure to 10 nM 1 alpha,25(OH)2D3 for 7 days, whereas 24,25(OH)2D3 synthesis was induced (0.46 pmol/h/incubation). The vitamin D3 metabolites were identified by co-chromatography with authentic 24,25(OH)2D3 or 1 alpha,25(OH)2D3 in three different high-performance liquid chromatography systems. Serum 1 alpha,25(OH)2D3 in the patient was markedly suppressed at 5 pg/ml (normal 20-50 pg/ml) indicating that raised 1 alpha,25(OH)2D3 was not the cause of the hypercalcaemia, but rather, that raised calcium may have suppressed renal 1 alpha,25(OH)2D3 synthesis. Administration of APD (3-amino-1-hydroxypropylidine-1,1-bisphosphonate) corrected the hypercalcaemia in the patient suggesting that increased bone resorption was responsible for the raised calcium. The results of this study show for the first time that immature blood derived monocyte-macrophage cells can synthesize 24,25(OH)2D3 before they mature into macrophages able to synthesize 1 alpha,25(OH)2D3.