Dominic V. Spagnolo

Gastrointestinal autonomic nerve tumors: a clinicopathological, immunohistochemical and ultrastructural study of 10 cases.

&NA; Gastrointestinal Autonomic Nerve Tumors (GANTs) are an under‐recognized group of gastrointestinal stromal tumors (GISTs) putatively arising from the neural plexuses of the bowel wall. Approximately 24 cases have been previously reported. Their histogenesis, malignant potential, morphology and phenotypic features are not well defined. We present details of 10 GANTs iterating features, predominantly ultrastructural, allowing distinction from other GISTs. Clinical details are: sex‐7M, 3F; age range 31–79 yrs, mean 53; symptoms/signs — abdominal pain 3, GI bleeding 3, mass 2, anemia 2. Follow‐up ranged from 1–102 mths, mean 29. Seven tumors involved the small intestine and 3 were gastric. Tumor size ranged from 30–160 mm, mean 79. They were solid and cystic, often transmural and usually involved mesentery and retroperitoneum. Spindled and epithelioid cells were “compartmentalized” by a branching microvasculature. Eosinophilic, PAS positive stromal globules were prominent. Paraffin immunostaining results were (number positive/total): vimentin (8/9), NSE (10/10), S100 protein (6/10), neurofilament protein (0/9), synaptophysin (3/9), desmin (2/9, focal), smooth‐muscle actin (0/9). Ultrastructural diagnostic features were elaborate, branching cytoplasmic processes containing microtubules, intermediate filaments and varying numbers of neurosecretory granules. Characteristic features were elaborate smooth endoplasmic reticulum enmeshed with intermediate filaments, pleomorphic mitochondria with lamellar cristae, mitochondrial‐RER complexes, confronting RER cisternae, and circumscribed collections of stromal “skeinoid” fibres. There were no features of smooth muscle, Schwannian or perineurial differentiation. We conclude that: 1) GANTs can be distinguished from other GISTs, electron microscopy being essential for diagnosis: 2) biological behaviour and predictors must await study of further cases with longer follow‐up; our findings indicate less aggressive behaviour than that described previously; and 3) immunohistochemistry on fixed material is of limited value without ultrastructural assessment; focal desmin positivity is not indicative of smooth muscle differentiation without other supporting evidence.

Nodular lymphomas with intracellular immunoglobulin inclusions: Report of three cases and a review

Summary Three cases of nodular lymphomas with cytoplasmic inclusions were studied histologically, histochemically and imrnunocytochemically, and ultrastructurally. One case had Russell body‐like inclusions, another had needle‐like inclusions not previously reported, while the last showed cells with cytoplasmic vacuoles. Two of the cases were followed to necropsy. New observations are described and the available literature is reviewed.

Mycobacterium terrae tenosynovitis

&NA; Atypical mycobacteria causing extra‐pulmonary disease in man are well documented.1 These infections are manifested by the presence of ulcers, abscesses and lymphadenitis. Mycobacterium marinum is particularly noted for infections involving the synovium, tendon sheaths, bursae and bone.2,3 Of lesser note is Mycobacterium terrae (radish bacillus),4 a nonchromogen also associated with tenosynovitis. We are not aware of any previous report of the association of M. terrae with synovitis in Australia.5 This case report describes a culture‐proven case of tenosynovitis caused by M. terrae.

Neoplastic angioendotheliosis is, in fact, intravascular malignant lymphoma

One of us reported a case of so-called neoplastic angioendotheliosis of the spinal cord [5] in Acta Neuropathologica in 1983. At that time, this entity was considered to be an unusual intravascular endothelial malignancy. Nevertheless, there were doubts as to the nature of the neoplastic cells. In 1982 Krieger et al. [3] reported the case of a 53-year-old man with an intravascular neoplasm similar to reported cases of neoplastic angioendotheliosis, but which seemed immunohistochemically to be composed of malignant histiocytes. In 1983 Yamamura et al. [9] described their necropsy tindings in a 44-yearold man with cerebral white matter lesions as being in keeping with neoplastic angioendotheliosis. The latter subject, additionally had a malignant lymphoma in a para-aortic lymph node, whose malignant ceils were similar to those present within blood vessels. Thereafter, Bhawan et al. [11 described another patient in whom a diagnosis of neoplastic angioendotheliosis was made in a skin biopsy, but Who later developed an intestinal malignant lymphoma. Immunological markers confirmed the lymphomatous nature of the intravascular cells. These authors suggested that neoplastic angioendotheliosis is an intravascular malignant lymphoma [1]. More recent studies [2, 4, 6 8 ] using both immunohistochemical and ultrastructural methods, provide further evidence that this entity is a form of malignant lymphoma. We have re-examined the sections of our case using the immunoperoxidase technique to demonstrate leucocyte-common antigen which is present on various haematolymphoid cells (in 1984 we did not have the monoclonal antibody to perform this investigation). We found that the neoplastic cells do indeed express this antigen, thus supporting the assertion that the intravascular malignant cells of this unusual neoplasm are consistent with a lymphoid nature rather than an endothelial one as was formerly suggested.