Splenic hamartoma with bizarre stromal cells

What is new in the 5th edition of the World Health Organization classification of mature B and T/NK cell tumors and stromal neoplasms?

The classification of tumors is essential in the diagnosis and clinical management of patients with malignant neoplasms. The World Health Organization (WHO) provides a globally applicable classification scheme of neoplasms and it was updated several times. In this review, we briefly outline the cornerstones of the upcoming 5th edition of the World Health Organization Classification of Haematolymphoid Tumours on lymphoid neoplasms. As is adopted throughout the 5th edition of the WHO classification of tumors of all organ systems, entities are listed by a hierarchical system. For the first time, tumor-like lesions have been included in the classification, and modifications of nomenclature for some entities, revisions of diagnostic criteria or subtypes, deletion of certain entities, and introduction of new entities are presented along with mesenchymal lesions specific to the stroma of lymph nodes and the spleen. In addition to specific outlines on constitutional and somatic genetic changes associated with given entities, a separate chapter on germline predisposition syndromes related to hematologic neoplasms has been added.

Splenic hamartoma with bizarre stromal cells: a case report and literature review

Background

Splenic hamartoma is a rare benign vascular proliferative lesion composed of unorganized sinusoid-like channels lined with plump or flat endothelial cells and characterized by a CD8-positive immunophenotype of the lining cells. Scattered bizarre stromal cells can be found in some splenic hamartomas. The presence of splenic hamartoma with bizarre stromal cells is extremely rare and these bizarre cells make it possible to be regarded as a malignancy. Recognition of this rare histologic variant will help to avoid diagnostic confusion and overtreatment of this benign entity.

Case presentation

We report a case of a 40-year-old man with occasional left-sided waist back pain. A splenic space-occupying lesion was detected by ultrasound and magnetic resonance imaging. Microscopically bizarre large cells were scattered throughout the splenic hamartoma. The cells exhibited atypical nuclei, scarcely visible cytoplasm, and vesicular chromatin, and they did not form expansile clusters and lacked mitotic activity. An immunohistochemical panel was performed. The bizarre cells strongly expressed vimentin, and the Ki-67 index was very low. The lesion was diagnosed as a splenic hamartoma with bizarre stromal cells.

Conclusions

To the best of our knowledge, this is the first systematic review on a splenic hamartoma with bizarre stromal cells; only six cases have been described in the literature. Proper identification is important to secure adequate treatment.

Enhanced CT and FDG PET/CT findings of splenic hamartoma

Splenic hamartomas are very rare benign vascular tumors. A 67-year-old man was referred after an incidental detection of a splenic lesion. Abdominal-enhanced CT showed a splenic lesion with progressive enhancement. This lesion showed intense FDG uptake with an SUVmax of 9.2. The patient underwent splenectomy. Splenic hamartoma was confirmed by pathologic evaluation. In this tumor, the disorganized splenic sinus contained a large amount of lymphocytes and plasma cells, which may contribute to the intense FDG uptake. This case indicates that splenic hamartoma should be included in the differential diagnosis of focal FDG accumulation along with tumor and nontumor conditions.

Desmoplastic Small Cell Tumor With Bizarre Giant Nuclei

A case is reported of an intra-abdominal desmoplastic small cell tumor featuring giant bizarre nuclei, an event not previously recorded in this entity to the best of the authors’ knowledge. The diagnosis was confirmed by immunohistochemistry and molecular genetics. A list is provided of the many other conditions in which this morphologically spectacular but clinically inconsequential nuclear change has been recorded.

Clonal X-chromosome inactivation suggests that splenic cord capillary hemangioma is a true neoplasm and not a subtype of splenic hamartoma

Splenic hamartoma is a rare tumor-like lesion composed of structurally disorganized red pulp elements. It has been hypothesized that two other splenic lesions, cord capillary hemangioma and myoid angioendothelioma, may fall within the spectrum of splenic hamartoma, simply representing morphological variants. In this study, we compared the vascular and stromal composition of cord capillary hemangioma and myoid angioendothelioma with those of classical hamartoma. In addition, we assessed the clonal vs polyclonal nature of the lesions in nine female cases by performing clonality analysis for X-chromosome inactivation at the human androgen receptor locus (HUMARA) on laser-assisted microdissected samples. In 15 of 17 cases, increased reticulin and/or collagen content was observed. The classical hamartoma cases showed a vasculature predominantly composed of CD8+ CD31+ CD34- splenic sinuses, whereas cases of cord capillary hemangioma and myoid angioendothelioma contained many CD8- CD31+ CD34+ cord capillaries, but very little CD8+ vasculature. All cases lacked expression of D2-40 and Epstein Barr virus-encoded RNA. All cases showed a proliferation index of ≤5% by Ki-67. Cases of classical hamartoma lacked significant perisinusoidal expression of collagen IV and low-affinity nerve growth factor receptor. Both markers were variably expressed in the other lesions. Increased CD163-positive histiocytes were found in four cases (three cord capillary hemangiomas and one myoid angioendothelioma). HUMARA analysis was informative in all nine tested cases, of which three cases showed a non-random X-chromosome inactivation pattern, indicating clonality. All three clonal cases were cord capillary hemangiomas. Our study has shown that in spite of considerable morphologic heterogeneity and overlapping features, classical hamartoma and cord capillary hemangioma and myoid angioendothelioma are different in terms of their vascular and stromal composition. Clonality analysis supports a true neoplastic origin for the cord capillary hemangioma. A larger study using additional immunohistochemical and molecular studies is necessary to further evaluate the biological significance of the current findings.

Splenic hamartoma in a child in the era of PET-CT

We present a case of a healthy 7-year-old female with an incidental finding of a growing splenic lesion, diagnosed as a splenic hamartoma after splenectomy. This case highlights the diagnostic challenge of splenic lesions and that the role of positron emission tomography/computerized tomography (PET/CT) in defining splenic lesions in the pediatric population remains to be defined.

Hamartoma of the spleen

Splenic hamartoma is a rare, benign vascular proliferation that is often found incidentally while working up other complaints or at autopsy. Women more commonly present with symptoms related to mass effect than men. Histologic findings consist of unorganized vascular channels of varying width, with intervening red pulp-like disorganized stroma with or without lymphoid follicles. The endothelial cells are similar to those of normal splenic sinuses. Although rendering a diagnosis can be difficult, endothelial cells that are positive for CD8 are a key feature that differentiate hamartoma from other vascular lesions of the spleen. Clinical, radiologic, and histologic correlation is essential to ensure this benign lesion is not mistaken for malignancy.

Hamartome de la rate (splénome) chez un enfant drépanocytaire

Hamartomas of the spleen or splenomas are uncommon benign lesions that predominantly occur in adults. We report a case of an 11-year-old girl with sickle cell anemia who had a single splenic 1.8 cm nodule incidentally found during splenectomy and histologically characterized by disorganized red pulp tissue without interspersed white pulp leading to the diagnosis of hamartoma. The association of hamartoma and hematological conditions is a very unusual condition in children.

Bizarre stromal cells in ischemic bowel disease

The presence of bizarre stromal cells has been reported in gastrointestinal and extraintestinal lesions. We describe, for the first time, the presence of bizarre stromal cells with a cytomegalovirus (CMV)-like appearance or ganglion-like cells in 3 cases of ischemic colitis. The 3 patients were males ranging in age from 62 to 78 years, showed varying degrees of cardiovascular insufficiency, and were diagnosed with ischemic colitis. Colonic biopsies showed changes of ischemic colitis of variable severity. Common to all 3 cases, within the granulation tissue, stromal cells showed a broad spectrum of morphologic alterations, ranging from just nuclear enlargement to striking atypical features, large pleomorphic, hyperchromic nuclei, and eccentric prominent nucleoli. Occasionally, these cells displayed an eosinophilic oval nuclear inclusion, surrounded by a clear halo, resembling CMV inclusions. In conclusion, the etiopathogenesis of these cells can be partially explained by hypoxia, inflammation, regeneration/repair, and cell turnover alone or, more probably, in combination in the granulation tissue response to injury. The morphologic spectrum of bizarre stromal cells and ganglion-like cells suggests an obvious differential diagnosis, which includes carcinoma and sarcoma. The finding of enlarged cells with eccentric intranuclear eosinophilic inclusions requires the exclusion of CMV. However, immunohistochemistry, together with an awareness of those atypical stromal cells, can occur in the setting of ulceration and/or polypoid lesions, preventing an incorrect diagnosis.