Michael Kyriakos

Fibroxanthosarcoma of the soft tissues. A type of malignant fibrous histiocytoma

The clinical and pathologic features of 30 soft tissue tumors which have a storiform fibrous stroma and bizarre histiocytes and giant cells are reviewed. Because of the resemblance of these lesions to the fibrous histiocytomas and because three of the tumors metastasized, they have been designated as fibroxanthosarcomas. Local recurrence was also common. Fibroxanthosarcoma occurs in many areas of the soft tissues but most commonly in the extremities. Histologically, it resembles storiform fibrous xanthoma (dermatofibrosarcoma protuberans) but can be separated from this entity by the presence of anaplastic bizarre giant cells and numerous mitoses. A proposed nomenclature for the fibrous histiocytomas is also presented. It is concluded that fibroxanthosarcoma is a distinctive malignant fibrous histiocytoma with a bizarre histologic pattern which can be distinguished from other soft tissue sarcomas and from the other fibrous histiocytomas.

Inflammatory fibrous histiocytoma. An aggressive and lethal lesion.

During an investigation of soft tissue fibrohistiocytic tumors, seven cases were found which we believe represent a new and specific diagnostic subgroup of the fibrous histiocytomas. All patients were adults (mean 52.6 years), only one of whom was younger than age 40. There were four females and three males; all were Caucasian. The tumors, which occurred in the retroperitoneum, anterior chest wall, anterior abdominal wall, femoral area, and oral cavity, were large, averaging 8.5 cm., and although appearing encapsulated, were microscopically infiltrative. The common histologic feature of all cases was a diffuse and at times intense neutrophilic infiltrate unassociated with tissue necrosis, in combination with bland and anaplastic appearing histiocytes. The presence of this acute exudative reaction is a unique feature of these lesions, and was present not only in the original tumors, but in recurrences and metastatic foci as well. Other cell types including foam cells, lymphocytes, plasma cells, eosinophils, Reed‐Sternberg‐like and ganglion‐like cells were commonly present. A storiform fibrous pattern, a hallmark of the fibrous histiocytomas was seen at some time in all but one case. The treacherous aspect of these lesions was their bland initial histologic appearance. The foci of foam cells associated with the inflammatory elements often led to a diagnosis of a benign inflammatory reaction or xantho‐granuloma. However, follow‐up has confirmed the aggressive and neoplastic nature of these lesions. The clinical course was usually protracted with multiple recurrences and eventual metastases. All patients died of their tumor, the average survival being 53 months; four patients survived over 5 years. At this time, we propose the term inflammatory fibrous histiocytoma to designate these lesions.

Aneurysmal (“Angiomatoid”) fibrous histiocytoma of the skin

Seventeen cases are reported of a variety of cutaneous fibrous histiocytoma, which we have designated as aneurysmal (“angiomatoid”) fibrous histiocytoma. These lesions differ from the classical cutaneous fibrous histiocytoma in both their clinical presentation and pathologic features.

Metastatic chondroblastoma. Report of a fatal case with a review of the literature on atypical, aggressive, and malignant chondroblastoma.

A boy with metastatic and fatal chondroblastoma is presented. Unlike previously published examples of metastatic chondroblastoma, these metastases developed before any operative manipulation of the primary tumor. The histologic characteristics of the primary, metastatic, and locally recurrent tumors were those of a conventional chondroblastoma. A review of published cases of atypical, aggressive, and malignant chondroblastoma is presented with current follow‐up information. Although some metastatic chondroblastomas may result from operative manipulation of the primary tumor and are clinically benign, other histologically benign chondroblastomas exist that are capable of pursuing a malignant course. The authors designate these as malignant chondroblastomas. No histologic criteria exist for the separation of these tumors.

Induction of experimental autoimmune thyroiditis in mice with in vitro activated splenic T cells

Spleen cells from CBA/J or SJL mice sensitized with mouse thyroglobulin (MTg) and lipopolysaccharide (LPS) could be activated in vitro with MTg to transfer experimental autoimmune thyroiditis (EAT) to normal syngeneic recipients. EAT induced by these transferred cells was similar in incidence and severity to EAT induced by active immunization of mice with MTg and adjuvant and cells from EAT-resistant Balb/c mice could not be activated to induce EAT. The specific antigen MTg was required both for initial sensitization of the mice and for activation of spleen cells in vitro. The cells that were active in transferring EAT to mice were shown to be T cells. Removal of B cells from the cultured spleen cells had no effect on the ability of the cells to induce EAT.

Malignant Peripheral Nerve Sheath Tumors with t(X;18). A Pathologic and Molecular Genetic Study

Spindle cell sarcomas often present the surgical pathologist with a considerable diagnostic challenge. Malignant peripheral nerve sheath tumor, leiomyosarcoma, fibrosarcoma, and monophasic synovial sarcoma may all appear similar histologically. The application of ancillary diagnostic modalities, such as immunohistochemistry and electron microscopy, may be helpful in the differentiation of these tumors, but in cases in which these adjunctive techniques fail to demonstrate any more definitive evidence of differentiation, tumor categorization may remain difficult. Cytogenetic and molecular genetic characterization of tumors have provided the basis for the application of molecular assays as the newest components of the diagnostic armamentarium. Because the chromosomal translocation t(X;18) has been observed repeatedly in many synovial sarcomas, it has been heralded as a diagnostic hallmark of synovial sarcoma. To formally test the specificity of this translocation for the diagnosis of synovial sarcoma, RNA extracted from formalin-fixed, paraffin-embedded tissue from a variety of soft tissue and spindle cell tumors was evaluated for the presence of t(X;18) by reverse transcriptase-polymerase chain reaction. Although 85% of the synovial sarcomas studied demonstrated t(X;18), 75% of the malignant peripheral nerve sheath tumors in our cohort also demonstrated this translocation. We conclude that the translocation t(X;18) is not specific to synovial sarcoma and discuss the implications of the demonstration of t(X;18) in a majority of malignant peripheral nerve sheath tumors.

A clinical and pathologic study of endocervical lesions associated with oral contraceptives

In a study of 30 patients histologic changes are described within the endocervix, which are associated with the use of oral contraceptives. Two lesions were found, the first of which has previously been called squamocolumnar prosoplasia or epidermidalization. This change, while not specific, was found in a high percentage of patients using these agents. The term “microglandular hyperplasia” is used to describe a second lesion which appears to occur only during pregnancy or with the use of oral contraceptives. The significance of these changes is discussed, with emphasis upon the fact that, while these changes may be mistaken histologically for adenocarcinoma, they are benign.

Malignant transformation of aneurysmal bone cyst, with an analysis of the literature

An 11‐year‐old girl had a lytic, benign‐appearing, expansive lesion of the distal tibia radiologically interpreted as an aneurysmal bone cyst (ABC). Tissue from two extensive curettage procedures was also histologically diagnosed as ABC. Approximately 50 months after the onset of symptoms, and 28 months after her last curettage, a highly pleomorphic osteosarcoma developed. The patient had not received prior radiation therapy. The cases in the literature of possible malignant transformation of ABC are reviewed. The authors separate their case from telangiectatic osteosarcoma, and from “ aneurysmal bone cyst‐like osteosarcoma”.

Giant vertebral notochordal rest: a lesion distinct from chordoma: discussion of an evolving concept.

A 14-year-old boy with severe back pain for several years is described. Roentgenograms, bone scans, and computed tomographic scans of the spine were normal, but magnetic resonance imaging studies showed a lumbar vertebral body lesion, confined to the bone, with low T1- and high T2-weighted signal intensities. Histologically, the lesion consisted of sheet-like notochordal-type tissue, containing physaliphorous cells but lacking the usual features of chordoma. A diagnosis of giant notochordal rest was made. A review of prior possible examples of this recently described and controversial entity is made with a discussion of its embryologic foundations and distinction from chordoma.

Bone infarct-associated osteosarcoma

Reported is a patient with an osteosarcoma arising in a medullary infarct of the humerus. Infarct‐associated sarcoma (IAS) of bone is rare. In a collective review of 50 cases reported in the medical literature, only 37 were fully documented. Including our patient, 26 men and 12 women, ranging in age from 18 to 82 years (mean, 53.4 years) have been reported. Black patients appeared to be disproportionately represented, accounting for 36% of the group. In most patients, there was no known cause for the infarct, whereas in the remainder, the most common underlying condition was a prior dysbaric event or alcoholism. Approximately 75% of the patients had multiple bone infarcts. The femur was involved in 21 patients, the tibia in 14, the humerus in 2, and the radius in 1. Among 40 sarcomas in these patients, 7 (18.4%) were os‐teosarcomas, and 29 (72.5%) were malignant fibrous histiocytomas. The survival rate in patients with IAS is poor: 5 of the 7 patients with osteosarcoma (71%) and 20 of the 31 other patients (65%) died of tumor. Eight patients are alive and well, all for longer than 5 years.