Polymorphic reticulosis

Description, Causes and Risk Factors:

A necrotizing lymphoproliferative lesion with a predilection for the upper respiratory tract; previously called lethal midline granuloma or malignant midline reticulosis; treatment is irradiation.

Polymorphic reticulosis (PMR) is a rare lymphoproliferative lesion that predominantly affects midline facial structures such as the nasal cavity, paranasal sinuses, pharyngolaryngeal, palate, and oral cavity. The disorder forms a part of the spectrum of the midline granuloma syndrome that progressively destroys midline facial structures. It is distinguished from nasal malignant lymphoma by its pathological features - although PMR primarily involves midline facial structures, dissemination to other organs has been reported. The disease of the lung, kidney, skin, retroperitoneum, central nerve system, liver, spleen, and GI tract are seen in various proportions of patients. In GI tract the involvement of stomach and jejunum have been reported.

PMR is not a localized disease of the midface but a systemic disease which can be disseminated to other organs. It is now considered to have the same disease process as lymphomatoid granulomatosis because of identical pathological features.

Pathologically, PMR is characterized by polymorphic and atypical lymphoreticular infiltrates which has a predilection of an angiocentric or angioinfiltrative growth pattern. Polymorphic infiltrate distinguishes the lesion from the Wegener's granulomatosis and typically monomorphic non-Hodgkin's lymphoma, but only imperfectly from the mixed lymphocytic lymphoma.

In order to study Efficacy & Toxicity of the primary treatment, researchers reviewed clinical features and therapeutic results in 29 patients. Nineteen patients received primary local irradiation and 10 patients primary combination chemotherapy. In the radiotherapy group, 14 (74%) patients achieved complete response, but only 4 (40%) did so in the primary chemotherapy group. Five patients in the latter group died of treatment-related complications. The 5-year actuarial survival rate was 70% in the irradiation group, while the 1-year survival rate was only 15% in the chemotherapy group. These data strongly suggest that, in polymorphic reticulosis, chemotherapy may be very toxic.

Symptoms:

PMR is clinically characterized by destruction and ulceration of midfacial structures. The principal local clinical features of PMR comprise nasal obstruction, discharge, and pain of the oropharynx, paranasal sinuses, and nose, which frequently lead to misdiagnosis of PMR as chronic sinusitis. Sometimes systemic symptoms such as fever, weight loss, and lethargy may present.

Diagnosis:

Because of severe inflammation and necrosis, an adequate technique of biopsy is required and frequently, repeated biopsy is recommended.The nature of the proliferating cells in PMR has been variably reported as being B cell, T cell, or true histiocytes. Many immunohistochemical studies and study of DNA re-arrangement of the beta T cell receptor gene showed that PMR is a T cell clonal process. But based on the study of re-arrangement of the immunoglobulin genes, PMR may be considered a malignant lymphoma of B cell lineage. The morphologic resemblance to mycosis fungoides was commented by some Researchers.

Treatment:

Local radiation therapy is the choice of treatment in the localized form of PMR confined to the face. When the disease is presented with widespread dissemination, chemotherapy, including cyclophosphamide and corticosteroid has been employed with various results. PMR has been considered a lymphoreticular disorder closely linked to malignant lymphoma because its similarity to the pathologic findings of lymphoma, the fact that it ultimately progresses to malignant lymphoma and its positive response to Radiation therapy.

NOTE: The above information is educational purpose. The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition.

DISCLAIMER: This information should not substitute for seeking responsible, professional medical care.