Antonio García-Escudero

Granular cell atypical fibroxanthoma: report of two cases.

Two cases of an uncommon histopathological variant of atypical fibroxanthoma (AFX) are described. Even though both lesions presented as clinically conventional atypical fibroxanthoma, histopathology disclosed a neoplasm composed of cells with granular change that was negative for S100 staining, and showed prominent pleomorphism, severe nuclear atypia, and a high mitotic index. Degenerative change may explain the granular phenotype in these two cases of AFX. The differential diagnosis with primitive nonneural granular cell tumor is discussed.

Cutaneous pseudolymphoma in association with molluscum contagiosum in an elderly patient

Background:  Molluscum contagiosum (MC) is a common cutaneous infection, which has been reported in association with cutaneous pseudolymphoma in few cases.

Thyroid transcription factor-1 expression in pulmonary blastoma.

Sir: We would like to report a previously undescribed immunohistochemical reactivity to thyroid transcription factor-1 (TTF-1) in pulmonary blastoma. A 40-year-old female presenting with a 58-mm subpleural, whitish tumour in the middle right lobe was treated by lobectomy; no metastases were found. Histological examination disclosed a biphasic tumour with two neoplastic components, epithelial and stromal (Figure 1). The stroma was formed by primitive cells with oval nuclei and scanty, indistinct cytoplasm, arranged haphazardly or in short fascicles. The epithelial component was made up of long arborizing glands (Figure 1) with suband ⁄ or supranuclear cytoplasmic vacuoles producing an ‘endometrioid’ appearance (Figure 2). In addition to this biphasic pattern, large areas of well-differentiated fetal adenocarcinoma with a monophasic epithelial (glandular) pattern were also observed growing in a sparse, mature stroma (Figure 2). Occasional solid squamoid morules were particularly evident in these areas.

Primary squamous cell carcinoma of the lung with pilomatricoma-like features

was found. The interlobular connective tissue contained a chronic in ̄ammatory in®ltrate. All these histological features were suggestive of necrotizing sialometaplasia. Necrotizing sialometaplasia is a very rare (0.03%) benign self-healing and reactive in ̄ammatory process which affects most frequently the intraoral minor salivary glands, primarily those of the hard palate (77%). Histologically, squamous metaplasia in necrotizing sialometaplasia has to be distinguished from the changes that may be found in salivary glands under different conditions such as sialadenitis, radiation damage or within tumours. A spectrum of histological ®ndings is observed in necrotizing sialometaplasia, ranging from coagulation necrosis of salivary gland acini in early lesions to squamous metaplasia of ducts and reactive ®brosis in late lesions. The helpful criteria in distinguishing necrotizing sialometaplasia from a malignant process are maintenance of the overall lobular morphology, the generally bland appearance of the squamous nests and evidence of residual ductal lumina in these nests. Little research has been done on its pathogenesis. Ischaemia of the vasculature supplying the salivary gland lobules is the most widely accepted pathophysiologic theory. The reported aetiological factors resulting in ischaemia are traumatic injury, dental injection, administration of local anaesthetic, smoking, alcohol consumption, radiation, upper respiratory infection, allergy or recent surgery in the oral sites. Our patient presented two possible aetiological factors: chronic alcohol consumption and administration of local anaesthetic for dental extraction. In summary, recognition of necrotizing sialometaplasia both clinically and histologically is essential to avoid inappropriate or unnecessary treatment for this benign reactive process. This lesion resolves spontaneously and does not require treatment. An adequate biopsy and awareness of this potential diagnostic pitfall is of great importance to insure an accurate histopathological diagnosis. This case report emphasizes the importance of a careful correlation between clinical and pathological ®ndings to avoid misdiagnosis. It should be borne in mind that local anaesthetic injection, which is routinely performed in dental treatment, may be a provoking factor for necrotizing sialometaplasia.

Cytological diagnosis of a presacral myelolipoma: A case report diagnosed by fine‐needle aspiration

Dear Dr. Bedrossian: Presacral myelolipomas (PML) are rare benign soft-tissue neoplasm with less than 20 previous cases reported. These are usually incidentally found on imaging studies performed in the work-up of vague digestive and/or urinary symptoms. Myelolipoma is an encapsulated tumor consisting in an admixture of mature adipose tissue and hematopoietic cells of all lineages. It also frequently shows scattered lymphoid aggregates. Previous studies have shown that an accurate diagnosis can be established by fine-needle aspiration (FNA). A 64-year-old Caucasian female presented with vague abdominal pain, constipation, nausea, and vomiting. The patient’s past medical history was significant for congestive heart failure secondary to constrictive pericarditis, chronic atrial fibrillation, peripheral venous insufficiency, and tuberculosis of the lung. Biochemical analysis and blood count did not reveal abnormal results. An abdominal-CT showed a presacral heterogeneous mass, 8 3 6.5 cm, thought to contain both fat and soft tissue. A CT-guided FNA was performed using an 18-gauge needle (Fig. 1). The air-dried Diff Quick-stained smears showed trilineage hematopoietic elements admixed with scattered lymphoid cells against a background of mature fat cells (Figs. 2 and 3A and B). Megakaryocytic cells were demonstrated by Factor VIII immunostain (Fig. 3C). A diagnosis of myelolipoma was made on the basis of these cytological features in conjunction with the radiological features. The patient refused the surgical excision of the neoplasm. Myelolipomas are benign soft-tissue neoplasms composed of an admixture of normal bone marrow elements and mature adipose tissue. They frequently occur in the adrenal gland being exceptional in extra-adrenal locations.

Lipoma endobronquial: una causa poco frecuente de obstrucción bronquial

Endobronchial lipoma is a rare benign neoplasm of the tracheobronchial tree. Despite its benign nature, associated endoluminal polypoid growth can cause bronchial occlusion. In this paper, we present the consequences of a late diagnosis of this condition.

Papillary and cystic insulinoma of the pancreas

tent nature of pleomorphic adenoma. A challenge for the pathologist is determining whether the fatty stroma in lipomatous pleomorphic adenoma is indeed a metaplastic stromal element as opposed to evidence of an invasive growth pattern. Normally, pleomorphic adenoma is encapsulated and demarcated from adjacent salivary glandular tissue, or it may extend as tongues or small satellite nodules beyond the capsule. A diffusely infiltrative growth pattern would be very unusual. However, since parotid tissue normally contains abundant adipose tissue, the question of infiltrative growth is raised in lipomatous pleomorphic adenoma. Probably the best clues that it is not an invasive neoplasm are its welldifferentiated biphasic pattern, the absence of cytological atypia, and the presence of a fibrous capsule in intact specimens. Recognition of this rare form of pleomorphic adenoma is also important for clinical diagnosis and management. The CT did not show the lesion in our case, possibly due to the extensive fatty component that blended with the normal parotid gland. However, ultrasound with fine-needle aspiration biopsy was diagnostic. It should be considered in the differential diagnosis of salivary gland lesions with lipomatous features, and not be mistaken for an invasive neoplasm.

Expression of dog1 in low-grade fibromyxoid sarcoma: A study of 19 cases and review of the literature

DOG1 is a highly-sensitive marker often included in the immunohistochemical panel for the diagnosis of gastrointestinal stromal tumors (GISTs). Recent research has shown that DOG1 may also be expressed by low-grade fibromyxoid sarcomas (LGFMSs); this may give rise to diagnostic error when the sarcoma is located in the abdominal cavity. This paper reports on immnohistochemical expression of DOG1 in 19 LGFMSs using two different monoclonal antibodies: K9 (Leica, Novocastra Laboratories, Newcastle upon Tyne, UK) and SP31 (Thermo Scientific, Freemont, USA). All LGFMSs displayed the standard histological pattern of alternating myxoid and fibrous areas, low cellularity and bland spindle-cell morphology. Positive staining for MUC4 was observed in 18/19 cases (94.7%), while there was rearrangement of the FUS gene in 14/19 (73.7%) cases and of the EWR1 gene in 2/19 (10.5%). The sarcoma staining negative for MUC4 displayed FUS gene rearrangement. Whole-section immunohistochemistry revealed positive staining for DOG1 in 8/19 cases (42.1%), though only with clone K9. Cytoplasmic as well as membrane staining was observed in all cases; staining was focal (10-30%) and of varying intensity (1+ to 2+). In conclusion, DOG1 clone K9 exhibited low sensitivity (42.1%) for the diagnosis of LGFMS, although higher than clone SP31. Since the two clones display similar sensitivity and specificity for GIST diagnosis, SP31 would appear to be more specific for this purpose, since no reaction was observed here with LGFMS, a GIST-mimicking lesion.