David S. Strayer

The histologic spectrumof the cutaneous mycobacterioses

The authors examined the histopathology of cutaneous involvement in 31 cases of nonleprous mycobacterial infection. Cases include three patients with Mycobacterium kansasii infection, two with M. fortuitum infections, and one each with M. marinum and M. chelonei infections, as well as 18 with M. tuberculosis infections. In the remainder, species were not identified. The histopathologic picture was variable and often did not suggest mycobacterosis. The authors identified seven basic pathologic patterns of skin involvement: 1) abscess, 2) well-formed (tuberculoid) granulomas, 3) diffuse histiocytic infiltration, 4) panniculitis, 5) nonspecific chronic inflammation, 6) naked (sarcoidal) granulomas, and 7) rheumatoid-like nodules. Intermediate forms were also found. Some cases showed adnexal or epidermal involvement, while others showed variably distributed dermal infiltration. The results indicate that a wide variety of cutaneous, clinical, and histologic guises may be assumed by mycobacterial infections in normal and immunocompromised hosts.

Adnexal Metaplasia in Carcinoma in situ of the Skin

Two cases of epidermoid carcinoma in situ of the skin, one with mucinous metaplasia and the other with sebaceous metaplasia, are reported. These unique cases suggest a spectrum of differentiation possible by neoplastic epidermal keratinocytes, which may help in the understanding of the histogenesis of certain skin neoplasms.

Gastric cytomegalovirus infection in bone marrow transplant patients: An indication of generalized disease

Cytomegalovirus infection in immunosuppressed patients is well known. It usually appears as an interstitial pneumonitis that may progress to a disseminated viral infection. The authors report on two patients who, after bone marrow transplantation, had signs and symptoms of gastric ulceration as the initial manifestation of cytomegalovirus infection. Both died with disseminated cytomegalovirus infection. Though gastric presentation is unusual for cytomegalovirus infection, epigastric pain and gastrointestinal hemorrhage in a bone marrow transplant patient may herald a potentially lethal viral infection.

Acute myelomonocytic leukemia presenting as a primary cutaneous lymphoma of true histiocytes

Malignant histiocytic and monocytic infiltrates of the skin are seen in true histiocytic lymphomas, in malignant histiocytosis, and in monocytic leukemias. Occasionally such cutaneous lesions constitute the presenting manifestation of the underlying malignancy. We report here a patient whose first manifestation of acute myelomonocytic leukemia was a malignant histiocytic infiltrate in the skin. Cytochemical and electron microscopic data confirmed the histiocytic nature of the skin tumor, and cytochemical data documented the myelomonocytic nature of the subsequent leukemia. Purely histiocytic skin tumors do not often presage myelomonocytic leukemias, although they have developed into monocytic leukemias, and monocytic leukemias have been transformed into myelomonocytic leukemias.

Recognition of normal, neoplastic, and fetal airway epithelial cell membranes by two monoclonal antibodies

The reactivity of two rat monoclonal antibodies was studied. These antibodies, A2R and A2C, bind a 32 kDa alveolar type II cell membrane receptor for surfactant protein A. A2R and A2C also bind apical cell membranes of ciliated and nonciliated cells of the conducting airways. Because this reactivity suggested possible utility in targeting those cells for therapeutic gene transfer, the binding activity of these two antibodies was examined in human tissues. In conducting airways, A2R and A2C bound apical epithelial cell membranes throughout the embryologic period studied: from 15 weeks of gestation, through maturity. Reactivity was more restricted to ciliated cells of the airways as maturation progressed. In the peripheral lung, A2C and A2R only bound most cells in the early developing lung, but mainly type II cells in mature lungs. Other normal tissues recognized by these antibodies included crypt lining cells of the adult and fetal stomach, large bile duct epithelium, and pancreatic acinar cells. All of these cells derive from embryonic foregut endoderm. Other normal tissues, both of endodermal and nonendodermal origin, were negative. Pulmonary carcinomas were studied. A2C and A2R recognized all non-small cell carcinomas of the lung tested. In contrast, none of the small cell carcinomas or carcinoid tumors of the lung were recognized by these antibodies. The function of p32 in these diverse cell types is not clear, but whatever its role in these tissues, antibodies versus p32 may potentially be used to target gene or drug therapy to the normal or malignant cells they recognize.